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WITH  THE  COMPLIMENTS 

THK   AUTHOR 
SmifPS  INSTITUTION 
FOR  KlOl/OGICAL  ^f  *jf^,  . 
SMITHSONIAN  INSTITUTION          ()p  i;s|  VKRSITV  OF  CAL1F0J 

UNITED  STATES  NATIONAL  MUSEUM     LA  JOLUA,  C 
Bulletin  100 

VOLUME  1,  PART  4 


CONTRIBUTIONS  TO  THE  BIOLOGY  OF  THE 

PHILIPPINE  ARCHIPELAGO  AND 

ADJACENT  REGIONS 


REPORT  ON  THE 

CHAETOGNATHA  COLLECTED  BY  THE  UNITED 
STATES  FISHERIES  STEAMER  "ALBATROSS" 
DURING  THE  PHILIPPINE  EXPEDI- 
TION, 1907-1910 


By  ELLIS  L.  MICHAEL 

Of  the  Scripps  Institution  for  Biological  Research,  La  Jolla,  California 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1919 


SMITHSONIAN  INSTITUTION 

UNITED  STATES  NATIONAL  MUSEUM 
Bulletin  100 

VOLUME  1,  PART  4 


CONTRIBUTIONS  TO  THE  BIOLOGY  OF  THE 

PHILIPPINE  ARCHIPELAGO  AND 

ADJACENT  REGIONS 


REPORT  ON  THE 

CHAETOGNATHA  COLLECTED  BY  THE  UNITED 
STATES  FISHERIES  STEAMER  "ALBATROSS" 
DURING  THE  PHILIPPINE  EXPEDI- 
TION, 1907-1910 


By  ELLIS  L.  MICHAEL 

Of  the  Scripps  Institution  for  Biological  Research,  La  JoJla,  California 


(Oft 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1919 


/*)  y  LIBRARY 

UNIVERSITY  OF  CALIFORNIA 
6/1  SANTA  BARBARA 

CC,   MS" 

REPORT  ON  THE  CHAETOGNATHA  COLLECTED  BY  THE 
UNITED  STATES  FISHERIES  STEAMER  "ALBATROSS" 
DURING  THE  PHILIPPINE  EXPEDITION,  1907-1910. 


By  ELLIS  L.  MICHAEL, 

Of  the  Scripps  Institution  for  Biological  Research,  La  Jolla,  California. 


INTRODUCTION. 

This  paper  is  based  upon  the  chaetognatha  collected  by  the  United 
States  Bureau  of  Fisheries  steamer  Albatross  during  the  Philippine 
expedition  of  1907-1910.  Chaetognatha  were  taken  at  46  stations 
scattered  between  the  parallels  of  21°  31'  north  and  5°  36'  south 
latitude,  and  between  the  meridians  of  117°  53'  east  and  127°  44' 
east  longitude.  The  collection  is  represented  by  12  species  of  Sagitta, 
of  which  one,  Sagitta  philippini,  is  apparently  new;  one  of  Pterosagitta; 
two  of  Eukrohnia;  and  one  of  Rrofinitta.  The  species  of  Sagitta,  in 
order  of  the  number  of  specimens  obtained,  are:  S.  enflata,  (2,800); 
S.  Tiexaptera,  (700);  8.  ferox,  (600);  S.  pulchra,  (550);  8.  neglecta, 
(425);  S.  bedoti,  (350);  S.  decipiens,  (160);  S.  serratodentata,  (100); 
S.  planktonis,  (85);  8.  minima,  (2);  and  one  each  of  S.  macrocephala 
and  8.  philippini.  Pterosagitta  is  represented  by  32  specimens  of 
P.  draco;  EukroJinia  by  6  specimens  of  E.  Jiamata  and  5  of  E.  rich- 
ardi;  and  KroTinitta  by  3  specimens  of  R.  subtilis. 

Most  of  the  material  was  preserved  in  formalin  and  is  in  excellent 
condition.  In  some  cases,  however,  alcohol  was  used.  Specimens 
preserved  with  it  are  distorted  and  the  tannin  extracted  from  the 
corks  of  the  containers  has  turned  most  of  them  quite  black,  ren- 
dering identification  uncertain  and,  in  some  cases,  impossible.  But, 
in  so  far  as  the  collection  permits,  tables  of  diagnostic  measurements 
are  given  for  each  species,  enough  measurements  being  made  on  each 
individual  to  enable  reconstruction  of  its  outline.  Otherwise,  the 
species  are  not  further  described  except  for  those  concerning  which 
need  of  description  is  indicated  by  the  literature.  In  lieu  of  descrip- 
tions, however,  references  are  given  to  those  published  in  other 
reports,  particularly  to  Ritter-Zahony's  (1911)  revision  of  the  group, 
which,  with  two  or  three  exceptions,  is  adopted  as  my  basis  of 
classification. 

In  order  to  make  the  report  as  serviceable  as  possible,  keys  are 
supplied  for  identifying  not  only  those  species  obtained  during  the 
Philippine  expedition  but  all  the  species  in  the  group.  Several  new 
species  and  five  new  genera  have  been  described  since  my  last  (1911) 
report.  In  addition,  Ritter-Zahony  (1911)  has  called  attention  to 
and  admirably  illustrated  specificities  in  the  presence  and  absence 

235 


236  BULLETIN   100,   UNITED  STATES   NATIONAL  MUSEUM. 

of  rays  in  the  lateral  fins.  In  devising  the  keys  these  specificities 
are  used  and,  except  for  Sagitta  maxima  (Conant),  which  I  still  find 
impossible  to  separate  from.  S.  lyra,  every  species  recognized  as  valid 
by  Bltter-Zahony  (1911)  and  several  others  described  subsequent  to 
his  report  are  included.  There  is  great  need  of  keys  for  identifying 
poorly  preserved  material,  but  the  minute  structure  of  seizing  jaws 
and  other  skeletal  parts  of  the  head,  upon  which  such  identification 
depends,  is  still  undescribed  in  nearly  half  the  species.  The  keys 
included  in  this  report  are  therefore  adapted  only  to  the  identification 
of  well-preserved  specimens. 

The  area  covered  by  the  expedition  is  too  large  and  the  hauls 
were  too  scattered  to  yield  definite  information  concerning  the  dis- 
tribution of  the  various  species  obtained.  As  pointed  out  elsewhere 
(1916,  p.  XVIII),  variability  in  plankton  distribution  is  enormous, 
and  hydrobiological  relations  are  too  complex  to  be  revealed  without 
frequently  repeated  collections  in  very  restricted  areas  and  searching 
hydrographic  observations  corresponding  in  time  and  place  to  each 
net  haul.  Even  though  thousands  of  individuals  of  one  species  and 
none  of  another  be  obtained  by  a  single  haul,  no  conclusion  is  justi- 
fied other  than  that  the  former  species  was  obtained  and  that  the 
latter  was  not  obtained.  Such  data  afford  no  adequate  evidence 
for  concluding  that  the  former  species  is  more  abundant  in  or  more 
typical  of  that  particular  locality  than  is  the  latter.  Had  20  or  30 
hauls  been  made  at  each  station  with  nets  of  similar  filtering  capaci- 
ties, sufficient  evidence  for  such  conclusions  might  have  been  obtained. 
But  rarely  more  than  one  haul  was  made  at  each  station,  so  the  data 
3rield  little  else  than  records  of  occurrence.  These  records  are  given 
for  each  species. 

In  comparing  the  species  occurring  in  the  Philippine  region  with 
those  obtained  from  the  vicinity  of  San  Diego  (the  only  coastal 
region  of  the  Pacific  off  either  of  the  American  continents  from  which 
chaetognaths  have  been  described),  two  interesting  and  suggestive 
facts  come  to  light:  First,  those  species  obtained  in  largest  numbers 
from  the  Philippines  are  those  which,  as  a  rule,  occur  rarely,  if  at  all, 
in  the  San  Diego  region,  and  the  opposite.  Second,  of  those  species 
common  to  both  regions,  the  number  of  teeth  is  greater  in  Philippine 
specimens. 

This  is  contrary  to  what  might  have  been  expected.  For,  judging 
from  the  fact  that  chaetognatha  collected  under  the  auspices  of  the 
Scripps  Institution  from  as  far  south  as  23°  north,  off  Lower  Cali- 
fornia, are  essentially  like  those  within  the  San  Diego  region  proper, 
and,  realizing  that  this  is  but  two  degrees  north  of  the  northern 
boundary  of  the  Philippine  area  from  which  chaetognatha  were 
obtained,  one  would  naturally  infer  a  close  relationship  between  the 
Philippine  and  San  Diego  faunas.  To  find  it  quite  the  reverse  is 
therefore  suggestive  of  a  fundamental  and  far-reaching  difference  in 


CHAETOGNATHA   COLLECTED  BY   STEAMER  ALBATROSS.          237 

the  other  faunas,  and  so  of  the  whole  economic  and  fisheries  situa- 
tions of  the  coastal  waters  on  opposite  sides  of  the  Pacific  at  corre- 
sponding latitudes.  Extensive  exploration  of  the  Pacific,  particu- 
larly of  the  coastal  waters  of  Central  and  South  America,  is  needed, 
however,  to  discover  the  full  significance  of  what  is  here  so  clearly 
indicated,  and  it  is  regretted  that  no  chaetognatha  are  described 
from  these  regions.  But,  in  spite  of  this,  it  seems  probable,  from  the 
meager  data  at  hand,  that  conclusions  reached  through  explora- 
tions in  the  western  Pacific  are  largely  inapplicable  to  the  waters  of 
the  eastern  Pacific,  and  the  opposite.  Some  space  is  therefore  taken 
at  the  close  of  the  paper  in  briefly  comparing  the  Philippine  and  San 
Diego  chaetognatha.  It  is  hoped  this  will  emphasize  the  need  of 
more  extensive  explorations,  and  that  it  may  add  its  mite  toward  a 
better  understanding  of  the  fishery  problems  of  the  Pacific  Ocean. 

KEYS  FOR  THE  IDENTIFICATION  OF  THE  CHAETOGNATHA. 

Ritter-Zahony  (1911)  has  been  the  last  investigator  to  thoroughly 
revise  the  chaetognatha.  He  recognizes  six  genera — Sagitta,  Ptero- 
sagitta, Spadella,  Eukrohnia,  HeterokroTinia,  and  KroTinitta.  Sub- 
sequently Germain  and  Joubin  (1912)  added  two  more — Pseudo- 
sagitta  and  EroTinitella.  All  are  probably  valid  with  the  possible 
exception  of  Spadella  and  Pseudosagitta,  the  status  of  which  is  baf- 
fling. Most  of  the  differences  given  by  Ritter-Zahony  (1911)  between 
Pterosagitta  draco  and  Spadella  cepJialoptera  are  certainly  no  greater 
than  that  between  those  species  of  Sagitta  in  which  the  skeletal  part 
of  the  vestibular  ridge  is  present  and  those  in  which  it  is  absent,  and 
this  difference  is  clearly  of  subgeneric  rather  than  generic  value. 
On  the  other  hand,  Conant's  (1895)  description  of  Spadella  schizop- 
tera,  although  fragmentary  and  wholly  unsatisfactory,  reveals  a  close 
affinity  between  that  species  and  S.  cepJialoptera  and  at  the  same 
time  makes  the  genus  to  which  it  belongs  unmistakably  distinct 
from  Pterosagitta.  Furthermore  I  have  seen  specimens  of  neither 
S.  cepJialoptera  nor  S.  schizoptera,  and  it  seems  best,  therefore,  to 
tentatively  recognize  Spadella  as  valid  in  spite  of  the  fact  that  the 
characteristics  by  which  its  one  well  known  species,  S.  cepJialoptera, 
differs  from  P.  draco  seem  of  subgeneric  value. 

The  validity  of  Pseudosagitta  is  ably  discussed  by  Baldasseroni 
(1915,  p.  101),  who  holds  its  single  new  species  P.  grimaldi  to  be 
synonymous  with  Sagitta  lyra.  The  differential  characters  described 
by  Germain  and  Joubin  (1912,  p.  6)  are  certainly  such  as  to  suggest 
this  synonymy  and  I  find  myself  in  agreement  with  Baldasseroni. 

In  the  following  keys  seven  genera  are  therefore  recognized,  of 
which  Sagitta  is  represented  by  23  species,  Eukrohnia  by  three, 
Spadella  by  two,  and  each  of  the  others  by  one:  Pterosagitta  draco 
(see  p.  264),  HeteroJcroJinia  mirabilis  (Ritter-Zahony,  1911,  p.  42), 


238  BULLETIN  100,  UNITED  STATES  NATIONAL  MUSEUM. 

KroJinitta  subtilis  (see  p.  269),  and  KroJinitella  loureei  (Germain  and 
Joubin,  1912,  p.  133). 

KEY  TO  GENERA. 

1.  Two  pairs  of  rows  of  teeth 2 

1.  Teeth  entirely  absent,  or  only  one  pair  of  rows  present 4 

2.  Two  pairs  of  lateral  fins,  the  posterior  pair  being  partly  on  body  and  partly 

on  tail.  Fins  completely  or  incompletely  rayed;  anterior  and  posterior 
pairs  sometimes  connected  by  narrow  membrane Sagitta. 

2.  One  pair  of  lateral  fins,  or  two  pairs  of  which  the  posterior  one  is  entirely 

confined  to  the  tail-segment.     Fins  completely  rayed 3 

3.  One  pair  of  lateral  fins  confined  entirely  to  tail-segment.    Collarette  massive, 

extending  to  tail-septum  and  spreading  out  over  fins.  Greatest  width 
slightly  anterior  to  tail-septum,  and  exceeding  half  that  of  the  body. 
Ventral  transverse  muscles  absent.  Anterior  and  posterior  teeth  both 

exceed  six  in  number Pterosagitta. 

3.  One  pair  of  lateral  fins  confined  entirely  to  tail-segment,  or  two  pairs  the 
posterior  one  of  which  is  confined  to  tail-segment.  Collarette  present  but 
not  massive.  Greatest  width  slightly  behind  head,  less  than  half  that  of 
body.  Ventral  transverse  muscles  present  in  body-segment  only.  Neither 
anterior  or  posterior  teeth  exceed  five  in  number Spadella. 

3.  One  pair  of  lateral  fins  partly  on  body  and  tail.     Collarette  absent.    Ventral 

transverse  muscles  present  in  both  body  and  tail Heterokrohnia. 

4.  Lateral  fin  begins  at  or  in  front  of  ventral  ganglion  and  extends  onto  tail  but 

never  to  seminal  vesicles.  Ventral  transverse  muscles  present  in  anterior 
third  of  body.  One  pair  of  rows  of  teeth EukroJinia. 

4.  Lateral  fin  begins  about  half-way  between  ventral  ganglion  and  tail-septum, 

and  extends  fully  to  seminal  vesicles.    Ventral  transverse  muscles  absent. .          5 

5.  Head  small  but  wider  than  body.    Less  than  50  per  cent  of  fin  in  front  of 

tail-septum.    Width  of  body  less  than  8  per  cent  of  total  length.     One 

pair  of  rows  of  teeth.     Seizing  jaws  delicate,  but  not  filliform Krohnitta 

5.  Head  small,  narrower  than  body.  More  than  60  per  cent  of  fin  in  front  of 
tail-septum.  Width  of  body  exceeds  9  per  cent  of  total  length.  Teeth 
absent.  Seizing  jaws  filliform Krohnittella. 

KEY  TO  SPECIES  OF  SAGITTA. 

1 .  Collarette  absent 2 

1.  Collarette  present 13 

2.  Shaft  of  seizing  jaw  serrated S.  serratodentata. 

2.  Shaft  of  seizing  jaw  not  serrated 3 

3.  Anterior  and  posterior  fins  confluent 4 

3.  Anterior  and  posterior  fins  separated 5 

4.  Both  pairs  of  fins  entirely  ray  less  throughout  at  least  their  anterior  thirds; 

tail  usually  exceeds  15  per  cent  of  total  length S.  lyra. 

4.  Fins  only  rayless  adjacent  to  body  but  not  along  outer  margins;  tail  usually 

less  than  15  per  cent  of  total  length S.  gazelle. 

5.  Anterior  fins  longer  than  posterior  fins S.  philippini. 

5.  Posterior  fins  longer  than  anterior  fins 6 

6.  Anterior  fins  entirely  rayless;  rays  of  posterior  fin  perpendicular  to  body. 

S.  minima. 

6.  Anterior  fins  not  entirely  rayless;  rays  of  posterior  fin  directed  obliquely 

to  body 7 

7.  Anterior  fins  extend  nearly  if  not  quite  to  ventral  ganglion 8 

7.  Anterior  fins  never  extend  within  half  their  length  of  ventral  ganglion 9 

8.  Both  pairs  of  fins  with  rays  throughout;  mature  ovary  short  and  thick,  not 

reaching  anterior  limit  of  posterior  fins S.  setosa. 


CHAETOGNATHA  COLLECTED  BY  STEAMER  ALBATROSS.          239 

8.  Anterior  extremities  of  both  pairs  of  fins  rayless;  anterior  fin  also  rayless 

throughout  a  narrow  strip  adjacent  to  body;  mature  ovary  long  and 
narrow,  extending  nearly  if  not  quite  to  ventral  ganglion S.  serratodentota 

9.  Tail  28-40  per  cent  of  total  length;  posterior  teeth  20-38,  rarely  as  few  as  17. 

S.  macrocephala. 

9.  Tail  less  than  28  per  cent  of  total  length;  posterior  teeth  rarely  exceed  16. .        10 
10.  Posterior  fins  extend  nearly  if  not  quite  to  seminal  vesicles;  both  pairs  of  fins 

rayed  throughout 11 

10.  Posterior  fins  never  extend  more  than  §  distance  from  tail-septum  to 

seminal  vesicles;  both  pairs  of  fins  rayless  throughout  a  narrow  strip 
adjacent  to  body 12 

11.  Body  very  transparent;  interval  between  anterior  and  posterior  fins  always 

less  than  half  the  length  of  posterior  fin S.  setosa. 

11.  Body  semi-translucent  but  never  transparent;  interval  between  anterior  and 

posterior  fins  usually  greater  than  half  the  length  of  posterior  fins S.  elegans 

12.  Vestibular  ridge  composed  entirely  of  papillae;  anterior  teeth  0-4,  rarely  5; 

posterior  teeth  0-6 S.  hexaptera, 

12.  Vestibular  ridge  provided  with  usual  skeletal  parts;  anterior  teeth  5-12, 

rarely  less  than  6;  posterior  teeth  7-18,  rarely  less  than  10 S.  enflata. 

13.  Collarette  short,  not  extending  over  half-way  from  neck  to  ventral  ganglion.        14 

13.  Collarette  long,  extending  more  than  £  distance  from  neck  to  ventral 

ganglion 22 

14.  Anterior  fins  longer  than  posterior  fins 15 

14.  Posterior  fins  longer  than  anterior  fins 18 

15.  Posterior  fins  never  extend  nearly  to  seminal  vesicles S.  decipiens, 

15.  Posterior  fins  extend  nearly  if  not  quite  to  seminal  vesicles 16 

16.  Body  transparent;  anterior  fins  exceed  30  per  cent  of  total  length  of  animal. 

S.  pulchra. 

16.  Body  opaque  or  semi-translucent,   but  never  transparent;  anterior  fine 

less  than  30  per  cent  of  total  length  of  animal 17 

17.  Both  pairs  of  fins  rayed  throughout S.  neglecta. 

17.  Anterior  extremities  of  both  pairs  of  fins  rayless S.  bedoti. 

18.  Interval  between  anterior  fins  and  ventral  ganglion  exceeds  one-fifth  length 

of  fins S.  bipunctata. 

18.  Anterior  fins  extend  nearly  if  not  quite  to  ventral  ganglion 19 

19.  Collarette  inconspicuous,  extending  less  than  one-fourth  distance  from 

neck  to  ventral  ganglion 20 

19.  Collarette  well  developed,  extending  between  one-fourth  and  one-half 

distance  from  neck  to  ventral  ganglion 21 

20.  Pronounced  constriction  at  tail-septum;  sexually  mature  at  a  length  of 

5-6  rnm ." S.  tennis 

20.  No  constriction  at  tail-septum;  never  sexually  mature  under  9-10  mm.-S'./ncfenci. 

21.  Anterior  teeth  10-18;  exceeding  number  of  posterior  teeth S.  helenae. 

21.  Anterior  teeth  4-9;  less  than  number  of  posterior  teeth S.  hispida. 

22.  Collarette  never  extending  to  ventral  ganglion S.  neglecta. 

22.  Collarette  extending  from  neck  to  seminal  vesicles S.  caUfornica. 

22.  Collarette  extending  fully  to  ventral  ganglion,  frequently  onto  anterior  fins, 

but  never  beyond  anterior  quarter 23 

23.  Posterior  fins  longer  than  anterior  fins S.  regularis. 

23.  Anterior  fins  longer  than  posterior  fins 24 

24.  Less  than  50  per  cent  of  posterior  fin  in  front  of  tail-septum S.  ferox. 

24.  More  than  50  per  cent  of  posterior  fin  in  front  of  tail -septum S.  planktonis. 

KEY   TO  SPECIES  OF  SPADELLA. 

1.  One  pair  of  lateral  fins  entirely  on  tail-segment.    Ventral  transverse  muscles 

present  throughout  entire  body-segment S.  cephaloptera. 


240  BULLETIN   100,   UNITED   STATES   NATIONAL  MUSEUM. 

1.  Two  pairs  of  lateral  fins,  the  posterior  pair  much  larger  and  confined  entirely 
to  tail-segment,  beginning  directly  behind  seminal  receptacle.  Anterior 
pair  extends  throughout  posterior  third  of  body,  beginning  directly  in 
front  of  seminal  receptacles.  Ventral  transverse  muscles  present  only  in 
anterior  half  of  body S.  schizoptera . 

KEY  TO  SPECIES  OF  EUKROHNIA. 

1.  Anterior  two-thirds  of  lateral  fins  rayless.  Posterior  extremity  of  fins  less 
than  half-way  from  tail-septum  to  seminal  vesicles.  Width  of  body  less 
than  8  per  cent  of  total  length  of  animal.  Seizing  jaws  delicate;  some- 
times serrated 2 

1.  Lateral  fins  delicately  rayed  throughout.     Posterior  extremity  of  fins  at 

least  three-fourths  way  from  tail-septum  to  seminal  vesicles.  Width  of 
body  exceeds  12  per  cent  of  total  length  of  animal.  Seizing  jaws  massive; 
not  serrated -  ^ E.  richardi. 

2.  Eyes  without  pigment.    Seizing  jaws   8-10,   gently   curved   throughout. 

Points  sickle-shaped E.  hamata. 

2    Eye  with  pigment.    Seizing  jaws  11-13,  sharply  curved  in  anterior  quarter. 

Point  slightly  curved  toward  edge  of  jaw,  but  not  sickle-shaped E.fowleri. 

SPECIES  OBTAINED  DURING  THE  PHILIPPINE  EXPEDITION. 
Genus  SAGITTA  Quoy  and  Gaimard. 

SAGITTA  PHILIPPINI,  new  species. 

Plate  34,  figs.  1-4. 

General  appearance. — To  the  naked  eye  S.  pJiilippini,  when  placed 
in  formalin  upon  a  white  background,  appears  white  in  color,  scarcely 
distinguishable  from  the  background.  Its  head  and  tail,  and  in  less 
degree  its  ovaries,  assume  a  brownish-yellow  color  in  marked  con- 
trast to  the  body  proper.  On  a  black  background  the  head,  ventral 
ganglion,  ovaries,  tail,  seminal  vesicles,  and  to  a  less  extent  the 
intestine  appear  much  more  opaque  than  the  body,  which  resembles 
ground  glass.  The  lateral  fins  and  tail  fin  are  so  transparent  as  to  be 
invisible  to  the  naked  eye.  In  degree  of  opacity  S.  philippini 
resembles  8.  decipiens  more  than  any  other  species,  although  it  is 
perhaps  less  transparent. 

Characters. — Collarette  absent.  Neck  conspicuous.  Lateral  fields 
prominent.  Body  flabby,  not  retaining  its  form  well;  widest  behind 
center,  tapering  gradually  forward  toward  head  and  backward 
toward  tail.  No  constriction  at  tail-septum.  Ovaries,  even  when 
immature  (pi.  34,  fig.  1),  extend  beyond  posterior  end  of  anterior  fin. 
Corona  ciliata  not  observed. 

Anterior  fins  (pi.  34,  fig.  1)  rayless  throughout  anterior  half  of  fin. 
They  are  longer  and  narrower  than  posterior  fins,  and  extend  ante- 
riorly beyond  posterior  end  of  ventral  ganglion.  Form  triangular, 
the  position  of  greatest  width  being  in  the  caudal  quarter  of  fin. 
Interval  from  anterior  to  posterior  fins  slightly  greater  than  maximum 
width  of  body. 

Posterior  fins  do  not  extend  caudally  to  seminal  vesicles.  More 
than  50  per  cent  of  fin  in  front  of  tail-septum.  Form  triangular, 
the  position  of  greatest  width  being  at  or  just  behind  tail-septum. 


CHAETOGlSrATHA   COLLECTED   BY   STEAMER  ALBATROSS.  241 

Vestibular  ridge  (pi.  34,  fig.  3)  well  developed  with  large  papillae. 
Wing  of  ridge  covers  all  but  the  first  two  or  three  teeth,  the  notch 
extending  to  the  fourth  or  fifth.  External  process  long  and  blunt. 

Anterior  teeth  (pi.  34,  fig.  2),  nine  in  number.  They  are  short, 
broad,  closely  set,  and  diverge  but  little  distally. 

Posterior  teeth  (pi.  34,  fig.  3),  20  in  number.  They  are  long, 
narrow,  closely  set,  and  diverge  even  less  than  do  the  anterior  teeth. 

Seizing  jaws  (pi.  34,  fig.  4),  six  in  number.  Point  with  an  oval 
base  imbedded  between  20  and  25  per  cent  of  its  height  into  shaft. 
Top  of  shaft  and  base  of  point  converge  toward  edge  of  jaw.  Edge 
of  shaft  provided  with  narrow  crest.  Pulp  canal  central  and  slightly 
swollen  at  base  of  point.  Pulp  evenly  distributed. 

Only  a  single  specimen  was  obtained.     Its  measurements  follow: 

Length 13  mm. 

Width 5.  5  per  cent  of  length. 

Length  of  tail 23  per  cent  of  length. 

Tip  of  tail  to  posterior  end  of  ventral  ganglion 70.  5  per  cent  of  length. 

Length  of  ventral  ganglion 6.  5  per  cent  of  length. 

Length  of  posterior  fin 22  per  cent  of  length. 

Width  of  posterior  fin 4.  5  per  cent  of  length. 

Interval  from  anterior  to  posterior  fins 6  per  cent  of  length. 

Per  cent  of  posterior  fin  in  front  of  tail-septum 60  per  cent. 

Length  of  anterior  fin 30  per  cent  of  length. 

Width  of  anterior  fin 2.5  per  cent  of  length. 

Anterior  fin  extends  beyond  posterior  end  of  ventral  ganglion 

by 2  per  cent  of  length. 

Ovary  extends  beyond  posterior  end  of  posterior  fin  by 14  per  cent  of  length. 

Anterior  teeth 9-9 

Posterior  teeth 20-(?) 

Seizing  jaws 6-6 

The  single  specimen  (Cat.  No.  17801,  U.S.N.M.)  was  taken  from 
the  surface  May  14,  1908,  off  Uanivan  Island,  at  station  D  5240, 
latitude  6°  49.5'  north  and  longitude  126°  15'  east.  The  same  haul 
also  yielded  130  S.  enflata,  105.  ferox,  6  S.  Tiexaptera,  1  P.  draco,  and 
75  S.  decipiens. 

8.  pJiilippini  bears  a  strong  resemblance  to  the  latter  species,  but 
differs  from  it  in  several  important  details:  In  the  first  place,  it  has 
no  trace  of  a  collarette,  although  this  structure,  while  not  pronounced 
in  S.  decipiens^  is  conspicuous.  Again,  the  ovaries  of  S,  philippini, 
though  not  fully  mature,  extend  nearly  to  the  middle  of  the  anterior 
fin,  while  in  8.  decipiens  they  do  not,  when  mature,  extend  beyond 
the  anterior  limit  of  the  posterior  fin.  Further,  the  posterior  fin  of 
S.  philippini  is  rayed  throughout,  while  in  8.  decipiens  (pi.  35,  fig.  8) 
the  anterior  fourth  or  fifth  of  the  fin  is  rayless.  Lastly,  the  seizing 
jaws  of  the  two  species  are  quite  different  (pi.  34,  fig.  4,  and  pi.  37, 
fig.  22),  the  jaw  in  S.  pMlippini  being  provided  with  a  narrow  but 
conspicuous  crest,  which  is  missing  in  S.  decipiens. 


242  BULLETIN  100,  UNITED  STATES  NATIONAL  MUSEUM. 

Altogether,  these  differences  would  seem  to  justify  the  description 
of  a  new  species,  even  though  it  may  later  prove  to  be  synonymous 
with  S.  decipiens.  Had  more  than  one  individual  been  obtained,  I 
should  feel  certain  of  the  validity  of  S.  philippini,  but  as  the  matter 
stands  this  single  specimen  might  with  as  much  justification  be 
regarded  as  an  abnormal  S.  decipiens. 

SAGITTA  ENFLATA  Grassi. 

Plate  38,  fig.  28. 

Sagitta  enflata  GRASSI  (1883),  p.  13. — FOWLER  (1906),  p.  8. — RITTER-ZAHONY 
(1911),  p.  13.— MICHAEL  (1911),  p.  28. 

This  species  is  represented  in  the  Philippine  collection  by  approxi- 
mately 2,800  individuals.  They  usually  exceed  20  mm.  in  length, 
and  the  largest  taken  measures  31.5  mm.  In  the  San  Diego  region, 
on  the  other  hand,  the  specimens  rarely  exceed  18  mm.  in  length,  the 
largest  recorded  (Michael  (1911,  p.  29))  measuring  only  21  mm. 
Again,  the  anterior  teeth  number  6  to  11,  typically  7  or  8,  in  the 
Philippine  specimens,  while  they  number  4  to  8,  typically  6  or  7,  in 
San  Diego  specimens.  Similarly,  the  posterior  teeth  number  9  to  15 
in  the  Philippine  specimens,  the  usual  number  being  14,  while  they 
number  6  to  12  hi  San  Diego  specimens,  the  usual  number  being  10 
or  11.  In  all  other  respects,  however,  specimens  from  the  two 
localities  are  in  agreement,  and  the  Philippine  specimens  agree  in 
size  and  number  of  teeth  with  specimens  described  by  Fowler  (1906 
p.  8)  from  the  Siboga  region. 

One  puzzling  fact  is  revealed  by  the  Philippine  collection.  The 
ovaries  in  most  of  the  larger  specimens  are  barely  approaching 
maturity,  only  one  case  of  complete  maturity  having  been  discovered 
in  individuals  exceeding  20  mm.  in  length;  but  among  individuals 
under  16  mm.  in  length  many  have  mature  ovaries  (pi.  38,  fig.  28). 
In  my  San  Diego  report  (1911,  p.  56)  a  table  is  given  of  specimens  of 
S.  enflata  arranged  in  three  groups  according  as  their  ovaries  were 
mature,  approaching  maturity,  or  remote  from  maturity.  In  the 
first  group  the  specimens  varied  in  length  between  12.5  and  19.5  mm., 
in  the  second  between  15  and  17.5  mm.,  and  in  the  third  between  8 
and  15.5  mm.  Obviously,  these  facts  are  open  to  two  interpretations: 
First,  the  ovaries  hi  San  Diego  specimens  attain  maturity  only  once 
and  that  after  a  length  of  12  mm.  is  reached;  and,  second,  the  ovaries 
in  the  same  individual  become  mature  periodically,  first  when  the 
individual  is  not  less  than  12  mm.  in  length,  and  subsequently  after 
it  has  grown  larger.  If  the  second  interpretation  is  eliminated,  how 
is  the  relation  between  length  of  individual  and  stage  of  maturity  of 
the  ovary  in  the  Philippine  specimens  to  be  accounted  for  ?  It  could, 
of  course,  be  readily  explained  on  the  assumption  that  two  species 
had  been  confused,  but  I  am  unable  to  discover  any  other  differences 
even  remotely  indicative  of  more  than  one  species.  In  Table  1,  for 


CHAETOGNATHA   COLLECTED  BY  STEAMER  ALBATROSS. 


243 


example,  No.  9  alone  had  mature  ovaries,  but  its  measurements  agree 
with  the  other  larger  and  immature  specimens. 

TABLE  1. — Measurements  of  Sagitta  enflata.1 


2.1.2 
23.  7 
23.  6 
23.2 
21.1 
20.6 
KS 
IS.  4 
15.8 

is.  a 

10.2 


10.7 
10.7 

8.7 
10.4 

9.  9 
12.4 
12.8 
11.8 
12.5 

9.7 

7.7 


74.5 
74 

69.8 
73 

74.8 

71.6 

70.  4 

73.  C 

71 

71.7 

72.3 


Posterior  fin. 


17.T) 

10.9 


17.3 


8.3 


4.8 


66.7 
62.5 
80.3 

fi2 

64.1 

64.8 

65 

63.4 

S3. 0 

70 

59.9 


Anterior  fin. 


11.8 
12.2 
14.9 
13.4 
15.  S 
13.6 
15.6 
17.7 
11.6 
16.2 
10.7 


15.4 
16.9 


18.2 


10-7 
8-7 
9-11 

7-  7 

8-  9 


14-14 
15-15 


14-15 
13-13 


8-8 
8-8 
9-9 

8-8 
8-8 
8-7 
9-8 
9-9 
8-9 
7-8 


1  All  measurements  made  in  per  cent  of  total  length  of  animal. 
'  Per  cent  of  posterior  fin  in  front  of  tail-septum. 

Distribution. — S.  enflata  was  collected  from  39  stations,  or  85  per 
cent  of  the  46  stations  at  which  chaetognaths  were  taken,  a  total 
of  approximately  2,800  specimens  having  been  obtained.  Of  the  39 
stations  8,  or  21  per  cent,  were  mesoplanktonic,  while  31,  or  79  per 
cent,  were  epiplanktonic,  and  22,  or  56  per  cent,  were  surface  stations. 
From  the  8  mesoplanktonic  stations  a  total  of  247  specimens  was 
obtained,  or  an  average  of  31  per  station,  while  from  the  31  epiplank- 
tonic stations  a  total  of  2,559  specimens,  or  an  average  of  83  per 
station,  was  obtained,  and  from  the  22  surface  stations  a  total  of 
1,476  specimens,  or  an  average  of  67  per  station,  was  obtained. 
These  data,  together  with  the  fact  that  all  subsurface  hauls  were 
made  with  open  nets,  make  it  clear  that  S.  enflata  occurs  typically 
in  the  upper  epiplankton  of  the  Philippine  region. 

The  northernmost  record  of  its  capture  during  the  Philippine  expe- 
dition is  14°  21 '.5  north  and  120°  23 '.3  east  in  the  China  Sea  near 
southern  Luzon.  The  southernmost  record  is  5°  36M  south  and 
127°  T. 6  east  in  Buton  Strait.  The  easternmost  and  westernmost 
records  are  127°  44'.0  east  and  1°  3'.0  south,  south  of  Patiente  Strait, 
and  117°  53'  east  and  21°  31'  north  in  the  China  Sea  off  Hongkong. 
The  largest  number  (950)  was  taken  February  7,  1908,  at  8.05  in  the 
morning  from  25  fathoms  by  an  open  0000  grit-gauze  net  towed 
horizontally  9  fathoms  above  the  bottom  of  the  Sulu  Archipelago, 
near  Basilan  Island,  at  6°  44'.2  north  and  121°  47'  east.  Other 
species  taken  in  the  same  haul  are:  318  S.  bedoti,  217  8  ferox,  116 
S.  pulcJira,  2  S.  Jiexaptera,  and  19  P.  draco.  The  complete  records  of 
its  capture  are  given  in  table  2 : 


244  BULLETIN   100,   UNITED    STATES   NATIONAL   MUSEUM. 

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CHAETOGNATHA  COLLECTED  BY   STEAMEE  ALBATROSS. 


245 


SAGITTA  HEXAPTERA  d'Orbigny. 

Sagitta  hexaptera  D'ORBIGNY  (1843),  p.  140.— FOWLER  (1906),  p.  11.— RITTEE- 
ZAHONY  (1911),  p.  7.— MICHAEL  (1911),  p.  30. 

This  species  is  the  second  most  abundant  and  frequent  obtained 
during  the  Philippine  expedition,  being  represented  by  approximately 
700  specimens.  Most  are  large  though  immature,  the  largest  speci- 
men measuring  45  mm.  in  length.  Curiously,  both  anterior  and 
posterior  teeth  in  many  specimens  are  entirely  missing.  My  first 
impression  was  that  although  not  seen  they  must  be  present,  but 
careful  dissection  of  several  heads  has  made  it  certain  that  the  teeth 
are  actually  missing.  This  was  not  noticed  in  San  Diego  specimens, 
two  being  the  smallest  number  of  either  anterior  or  posterior  teeth 
recorded  in  my  (1911)  report.  Again,  Fowler  (1906,  p.  13)  lists  the 
number  of  teeth  in  42  specimens,  one  being  the  smallest  number  of 
either  anterior  or  posterior  teeth  recorded.  Ritter-Zahony  (1908, 
p.  10),  however,  while  recording  three  as  the  smallest  number  of 
anterior  teeth,  gives  four  instances  in  which  the  posterior  teeth  in 
individuals  33,  34,  36,  and  38  mm.  in  length  were  missing.  In 
attempting  to  account  for  the  peculiar  variability  in  number  of  teeth, 
Fowler  (1906,  p.  14)  explains  their  absence  in  the  Philippine  speci- 
mens. He  says: 

I  believe  the  explanation  to  lie  mainly  (perhaps  not  entirely)  in  the  length  and 
slenderness  of  the  teeth;  many  of  them  are  probably  torn  out  by  the  roots;  certainly 
many  are  broken  off  short,  for  their  bases  may  be  seen  still  in  place.  As  an  additional 
weakness,  the  posterior  teeth  in  older  specimens  often  appear  not  to  be  attached  to  the 
bony  bar  with  which  they  are  united  in  other  species,  but  to  lie  at  some  distance  from 
it  in  a  superficial  plate  of  chitinous  material. 

TABLE  3. — Measurements  of  Sagitta  hexaptera.1 


17.0  65.1 

19.1  65.8 
19.1   72 


10.6  14.5 

9.6!  15.51  3.3 

11.8!  11.2   2.3 

7.2  14.31  2 

14.1 1  15.2    2.1 

6.9l  13.6!  3 
10.  o!  2.3 


14.9;  39.2     .62-16 

14.6  55. 51  2.16+  4.2 

11.8  19.7;  1.09-23.2 

11.4  24. 5i  1.12; -19.1 


-21.6 
.46; -32. 3 
.46- 
.711-27 
1. 311-12. 4 


All  measurements  made  in  per  cent  of  total  length  of  animal. 
Per  cent  of  posterior  fin  in  front  of  tail-septum. 

The  +  signifies  extension  beyond  anterior  end  of  ganglion;  the  —  signifies  distance  from  posterior  end 
of  ganglion. 


246  BULLETIN  100,  UNITED  STATES  NATIONAL  MUSEUM. 

Distribution. — S.  Jiexaptera  was  collected  from  26,  or  57  per  cent,  of 
those  stations  at  which  chaetognaths  were  captured.  Of  these,  8 
were  mesoplanktonic,  while  13,  or  one-half,  were  surface  stations. 
From  the  8  mesoplanktonic  stations  a  total  of  only  70,  or  an  average 
of  9  to  each  station,  was  obtained,  while  the  18  epiplanktonic  stations 
yielded  642,  or  an  average  of  36  per  station,  and  the  13  surface  sta- 
tions yielded  491,  or  an  average  of  38  per  station.  It  is  evident, 
therefore,  that  S.  Jiexaptera  occurs  typically  in  the  upper  epiplankton 
of  the  Philippine  region. 

S.  Jiexaptera,  often  confused  with  S.  elegans  and  with  the  large 
variety  (S.  maxima)  of  8.  lyra,  is  a  eurythermal,  nearly  cosmopolitan 
species  found  typically  in  the  lower  epiplankton  and  mesoplankton 
of  the  arctic,  sub-arctic,  north  temperate,  tropical,  and  south  tropical 
Atlantic,  the  south  temperate  and  tropical  Indo-Australian,  and  the 
north  temperate  and  sub-antarctic  Pacific  oceans.  Its  northern  and 
southern  limits  of  distribution  are  74°  north  and  28°  south,  while 
the  extremes  of  temperature  recorded  in  connection  with  its  capture 
are  29°  C.  and  6°  C.  A  statement  frequently  encountered  in  the 
literature  is  that  surface  Chaetognatha  of  the  arctic  seas  would  be 
found,  if  at  all,  in  the  mesoplankton  of  temperate  and  tropical 
regions,  the  implication  being  that  temperature  plays  the  all- 
important  part  in  delimiting  the  vertical  distribution  of  a  species. 
Obviously,  the  typical  occurrence  of  S.  Jiexaptera  in  the  upper  epi- 
plankton during  the  Philippine  expedition  contradicts  this  statement, 
which  contradiction  is  further  supported  by  Ritter-Zahony  (1911, 
p.  54),  who  says:  "Es  gibt  keinen  einzigen  verbiirgten  Fundort  der 
8.  Jiexaptera  aus  dem  Epiplankton  der  Meere  nordlich  von  40°  N." 
Rather  do  the  facts  point  in  quite  the  opposite  direction,  that  is 
that  surface  8.  Jiexaptera  of  tropical  and  sub-tropical  regions  are 
found,  if  at  all,  hi  the  lower  epiplankton  and  mesoplankton  of  arctic 
and  sub-arctic  regions.  However,  until  consistency  of  identifica- 
tion of  the  species  obtained  during  the  various  expeditions  is  attained, 
and  until  the  vertical  distribution  of  the  species  in  diversified  regions 
is  critically  studied,  no  conclusion  as  to  the  part  played  by  tempera- 
ture or  any  other  environmental  influence,  in  controlling  its  distri- 
bution throughout  the  world,  is  justified. 

The  northernmost  and  westernmost  record  of  its  capture  during 
the  Philippine  expedition  is  21°  31'  north  and  117°  53'  east  in  the 
China  Sea,  off  Hongkong.  Its  southernmost  record  is  5°  36 M  south 
and  122°  7'.6  east,  in  Buton  Strait;  and  its  easternmost  record  is 
127°  44'  east  and  1°  3'  south,  south  of  Patiente  Strait.  The  largest 
number  (153  +  )  was  taken  August  11,  1909,  at  7.49  in  the  evening, 
from  the  surface  between  Siquijor  and  Bohol  Islands,  at  9°  2 7 '.5 
north  and  123°  38'  east.  Other  species  obtained  at  the  same  station 
are:  169  8.  enflata,  128  S.  pulcJira,  50  S.ferox,  and  14  S.  bedoti. 


CHAETOGtfATHA  COLLECTED  BY   STEAMER  ALBATROSS.          247 

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248  BULLETIN   100,   UNITED  STATES   NATIONAL  MUSEUM. 

SAGITTA  MINIMA  Grass!. 

Plate  37,  figs.  16-17;  plate  38,  fig.  29. 
Sayitta  minima  GRASSI  (1881),  p.  213;  (1883),  p.  15.— KRUMBACH  (1903),  p.  637.- 

RlTTER-ZAHONT  (1911),  p.  25. 

This  species  is  represented  by  only  two  specimens  (Cat.  No.  17925, 
U.S.N.M.),  both  of  which  are  apparently  sexually  mature.  Both 
were  obtained  on  April  3,  1908,  from  the  surface  at  station  D.  5195, 
off  northern  Cebu  Island,  10°  47'  north  and  124°  6'.5  east.  Except 
for  the  mature  ovaries  they  are  almost  inseparable  to  the  naked 
eye  from  small  S.  enfiata.  Microscopic  examination,  however, 
reveals  several  marked  differences.  The  species  is  redescribed  on 
the  basis  of  these  two  specimens. 

Collarette  absent.  Body  flabby  and  widest  on  a  level  with  anterior 
end  of  posterior  fins,  tapering  gradually  toward  head  and  tail.  Con- 
striction at  tail-septum  slight  or  absent.  Ovary  (pi.  38,  fig.  29) 
short,  not  extending  to  anterior  end  of  posterior  fins.  Ova  large 
and  arranged  in  a  single  row  within  the  ovary.  Corona  ciliata  not 
observed. 

Anterior  fins  shorter  and  narrower  than  posterior  fins  and  entirely 
rayless.  They  fall  short  of  reaching  the  posterior  end  of  ventral 
ganglion  by  nearly  two-thirds  the  length  of  fins.  Interval  from 
anterior  to  posterior  fins  approximately  equal  to  half  the  length  of 
anterior  fins. 

Posterior  fins  (pi.  38,  fig.  29)  with  rays  arranged  perpendicular 
to  the  body.  Interval  from  fins  to  seminal  vesicles  3  to  5  per  cent 
of  total  length.  More  than  50  per  cent  of  fins  in  front  of  tail-septum. 
Position  of  greatest  width  behind  tail-septum. 

Vestilular  ridge  (pi.  37,  fig.  16)  provided  with  low,  regular  papillae, 
one  for  each  tooth.  Wing  covers  all  except  the  first  tooth,  the  second 
being  just  barely  covered.  Notch  extends  to  fourth  tooth.  Ex- 
ternal process  apparently  missing. 

Anterior  teeth,  4  to  5  in  number  (2  to  5  according  to  Ritter-Zahony, 
1911,  p.  26).  They  are  very  closely  set  and  not  diverging  much 
distally.  Posterior  teeth  (pi.  37,  fig.  16),  10  or  11  in  number  (6  to  14 
according  to  Ritter-Zahony).  They  are  not  so  closely  set  as  the 
anterior  teeth,  but  are  more  divergent  distally. 

Seizing  jaws  (pi.  37,  fig.  17),  8  or  9  in  number  (7  to  8  according  to 
Ritter-Zahony).  Point  with  an  oval  base,  inserted  into  shaft  by 
less  than  one-fifth  its  height.  Tip  of  point  curved  toward  its  edge. 
Base  of  point  and  top  of  shaft  parallel.  Pulp-canal  central,  with  a 
swollen  place  below  base  of  point.  Pulp  evenly  distributed  through- 
out canal. 

Aside  from  the  number  of  teeth  and  seizing  jaws  and  length  of 
tail,  only  one  of  the  two  specimens  is  well  enough  preserved  to  permit 
accurate  measurements. 


CHAETOGNATHA  COLLECTED  BY  STEAMER  ALBATROSS. 


249 


Length  in  mm 9.  5. 

Tail: 

Length 20.  8  per  cent  of  length . 

To  ventral  ganglion 68.  5  per  cent  of  length. 

Posterior  fin : 

Length 17.  6  per  cent  of  length . 

To  seminal  vesicles 3.  2  per  cent  of  length. 

To  anterior  fin 9. 1  per  cent  of  length. 

Proportion  in  front  of  tail-septum 59. 1  per  cent. 

Anterior  fin: 

Length 16.  5  per  cent  of  length. 

To  ventral  ganglion 11.  7  per  cent  of  length. 

Number  of  anterior  teeth. . . : 5-4. 

Number  of  posterior  teeth ll-(?) 

Number  of  seizing  jaws 8-9. 

The  other  specimen  measured  8.9  mm.;  its  tail  measured  20.7  per 
cent;  the  number  of  anterior  teeth  are  4-5;  the  number  of  posterior 
teeth,  10-10;  and  the  number  of  seizing  jaws,  9-8. 


SAGITTA  SERRATODENTATA  Krohn. 


Sagitta  serratodentata  KROHN  (1853),  p.  272. — FOWLER  (1905),  p.  58. — HITTER 
ZAHONY  (1911),  p.  22.— MICHAEL  (1911),  p.  39. 

Approximately  100  specimens  were  obtained,  none  of  which  is 
sexually  mature.  The  number  of  anterior  and  posterior  teeth  is 
greater  than  recorded  by  Fowler  (1905,  p.  58)  in  specimens  taken 
from  the  Bay  of  Biscay,  or  by  myself  (1911,  p.  40)  in  specimens  taken 
from  the  San  Diego  region.  In  specimens  between  7  and  11  mm.  in 
length  Fowler  records  3  to  6  anterior  and  2  to  10  posterior  teeth, 
while  in  Philippine  specimens  between  the  same  lengths,  the  anterior 
teeth  number  8  to  11  and  the  posterior  teeth  13  to  24.  The  San 
Diego  specimens  are  considerably  larger,  those  recorded  varying  in 
length  between  10  and  17  mm.;  but  the  number  of  teeth  is  inter- 
mediate, the  anterior  teeth  numbering  6  to  9  and  the  posterior  teeth 
13  to  19.  The  species  appears  to  be  unusually  variable. 
TABLE  5. — Measurements  of  Sagitta  serratodentata.1 


10.  5 
10.3 
10.2 


20.0 

24 

SB 

90 

24.5 
9B 

2:..  5 

27 

25.5 


Posterior  fin. 


Anterior  fin. 


20.  0 

28 

27 


27.5 
SI 
28 
28.  fl 


51.5 

55 

52 

52 

50.5 

50 

49.5 

52 

55 


IS.  5 
22.5 
21 


22 
21.5 


10-10  23-22 

11-11  24-23 

11-10  20-18 

8  -9  20-? 

9  -8 
9  -9 

9  -8  15-14 

9  -9  18-19 

9  -?  15-? 

9  -9  14-13 


17-16 


. 

o> 


6-5 
6-6 
6-6 
6-6 
6-6 
7-7 
0-6 
6-7 
6-1 
7-7 


1  All  measurements  made  in  per  cent  of  total  length  of  animal. 
i  Per  cent  of  posterior  fin  in  front  of  tail-septum. 


59318— 19— Bull.  100 2 


250 


BULLETIN   100,   UNITED   STATES   NATIONAL  MUSEUM. 


<  i-l  0*         Oi  iO  r-teO 


a  a  a  a  a  a  a  a 


BB5IBS 


Distribution. — S.  serratodentata  was 
collected  from  only  eight  stations.  All 
except  three  were  mesoplanktonic,  but 
the  largest  number  of  specimens  (73) 
were  taken  from  the  surface.  The  rec- 
ords are  given  in  Table  6 : 

SAGITTA  MACROCEPHALA  Fowler. 

Sagitta  macrocephala  FOWLER  (1905),  p.  65. — 
RITTER-ZAHONY  (1911),  p.  31. 

A  single  distorted  specimen  was  ob- 
tained. Its  measurements  follow: 

Length  in  mm 7.8  mm. 

Width  in  per  cent  of  length 14.4  per  cent. 

Tail  in  per  cent  of  length 37.  4  per  cent. 

Length  of  posterior  fin 24. 8  per  cent. 

Per  cent  of  fin  in  frontof  tail- 
septum 45.5  percent. 

Width  of  posterior  fin 7 .  7  per  cent. 

Interval  from  anterior  to  posterior 
fin 5.5  per  cent. 

Length  of  anterior  fin 15.0  per  cent. 

Width  of  anterior  fin 2.  7  per  cent. 

Number  of  anterior  teeth 7-7 

Number  of  posterior  teeth 25-26 

Number  of  seizing  jaws 11-11 

Ventral  ganglion,  corona  ciliata,  and 
ovaries  not  observed. 

The  specimen  differs  conspicuously 
in  width  from  those  drawn  by  Fowler 
(1905,  pi.  5,  fig.  16)  and  Ritter-Zahony 
(1911,  fig.  37).  In  width  the  Philip- 
pine specimen  measures  14.4  per  cent 
of  the  length,  while  Fowler  draws  it 
7.8  per  cent,  and  Ritter-Zahony  5  per 
cent.  However,  the  Philippine  specimen 
is  clearly  immature,  neither  ovaries  nor 
seminal  vesicles  being  visible.  More- 
over, it  is  poorly  preserved,  some 
portions  of  the  body  being  distorted 
and  others  torn  away.  These  facts 
are  probably  responsible  for  the  ex- 
cessive width.  Unfortunately  the  points 
of  all'  seizing  jaws  were  broken  off, 
so  that  their  structure  could  not  be 
determined. 


CHAETOGNATHA   COLLECTED  BY   STEAMER,  ALBATROSS.          251 

The  single  specimen  (Cat.  No.  17926,  U.S.N.M.)  was  obtained 
November  6,  1908,  in  the  China  Sea,  in  the  vicinity  of  Formosa,  at 
station  D.  5320,  20°  58'  north  and  120°  3'  east  by  an  open  0000  grit 
gauze  net  towed  at  3.18  in  the  afternoon  in  500  fathoms  for  twenty 
minutes. 

SAGITTA  PULCHRA  Doncaster. 

Plate  35,  fig.  5;  plate  37,  figs.  19,  23. 

Sagitta  pulchra  DONCASTER   (1902),  p.   213.— FOWLER   (1906),   p.  17.— RITTER- 
ZAHONY  (1911),  p.  21. 

Approximately  500  individuals  were  obtained,  and  few,  if  any,  are 
sexually  mature.  In  body  length  and  number  of  teeth  they  agree 
remarkably  well  with  specimens  described  by  Fowler  (1906)  from  the 
Siboga  region.  He  records  5  to  10  anterior  and  9  to  15  posterior 
teeth  in  specimens  between  9  and  22  mm.  in  length,  and  in  Philippine 
specimens  between  9  and  30  mm.  in  length,  the  anterior  teeth  number 
5  to  9,  and  the  posterior  teeth  10  to  13.  The  Philippine  specimens 
are,  on  the  whole,  so  well  preserved  that  the  species  is  redescribed. 

Collarette  (pi.  35,  fig.  5)  conspicuous  but  short,  varying  in  length 
from  one-twentieth  to  one-tenth  the  length  of  the  animal.  Its 
length  is  less  than  twice  the  body  width  and  it  extends  between  one- 
fourth  and  one-half  the  distance  from  neck  to  ventral  ganglion  Neck 
pronounced  but  rendered  inconspicuous  by  the  collarette.  Muscles 
thin  but  strong.  Lateral  fields  large.  More  transparent  than  any 
other  species  having  a  collarette,  and  similar  in  transparency  to  S. 
enflata.  Its  body,  however,  is  firmer  than  that  of  8.  enflata  and  is 
approximately  half  as  wide.  Width  greatest  between  one-half  and 
three-quarters  the  distance  from  head  to  tail-septum,  tapering 
gradually  forward  and  more  rapidly  backward.  Slight  constriction 
at  tail-septum.  Tail  18  to  25  per  cent  of  total  length  of  animal. 
Corona  ciliata  not  observed. 

Anterior  fins  (pi.  35,  fig.  5)  longer  and  narrower  than  posterior  fins 
extending  anteriorly  beyond  posterior  end  of  ventral  ganglion, 
frequently  beyond  its  middle,  and  rarely  beyond  its  anterior  end. 
No  rays  except  in  posterior  quarter  of  fin.  Interval  from  anterior 
to  posterior  fins  usually  less  than  two-thirds  width  of  body,  varying 
from  slightly  less  than  one-half  to  slightly  more  than  the  width. 

Posterior  fins  (pi.  35,  fig.  5)  rayless  anteriorly.  They  extend 
posteriorly  nearly  if  not  quite  to  seminal  vesicles,  the  interval 
never  exceeding  2.5  per  cent  of  total  length  of  animal.  More  than 
50  per  cent  of  fin  in  front  of  tail-septum,  varying  from  50.5  to  64  per 
cent.  Broadly  triangular  in  form,  and  widest  at  or  slightly  behind 
tail-septum. 

Vestibular  ridge  (pi.  37,  fig.  19)  provided  with  large  regular  papillae, 
the  apices  of  which  usually  terminate  in  two  minute  spines.  Wing 
of  ridge  covers  all  except  first  two  or  three  teeth.  Notch  extends 


252 


BULLETIN   100,   UNITED  STATES   NATIONAL   MUSEUM. 


to  fourth  or  fifth  tooth.  External  process  one-third  to  one-half 
length  of  ridge  and  approximately  four  times  longer  than  broad. 

Anterior  teeth  5  to  9,  closely  set  and  diverging  distally.  Posterior 
teeth  (pi.  37,  fig.  19)  10  to  13,  not  so  closely  set  nor  so  divergent  dis- 
tally as  anterior  teeth. 

Seizing  jaws  (pi.  37,  fig.  23)  5  to  6  in  number.  Point  with  oval 
base  inserted  little  more  than  one-tenth  its  height  into  shaft.  Base 
of  point  and  top  of  shaft  parallel.  Edge  of  shaft  provided  with 
broad  thin  crest.  Pulp-canal  central,  with  pulp  evenly  distributed 
throughout. 

TABLE  7. — Measurements  of  Sagitta  pukhra.1 


19.  r, 


5.5   18 
7       17.5 
6.    j  19.5 
5.5!  19.5! 

6    I  20 
5.5|  21 
6    I  19.5 
5.5!  21 
20 


70 

72 

71 

70.5 

71) 

72 

71 

70.  5 

67 

eg 


li 


Posterior  flu. 


Anterior  fin. 


2.5  64  37.5 
3.5  56  !  37.5 
2.5!  63.5  36 

2  i  58. 5'  36 

3  I  59.5  32 
1.5:  56.5   35 
4.5   59.5i  33.5 
7       54    |  32.5 
3       58. 5!  36 
4.5  55.51  33 
3.5   60    I  32 

0  '  56      32 

62    i  32 
51.1   31.5 

1  I  50.5f  32 


+4.5 
2.5  +1 
2.5j  +1.5 
3       +1.5 

2  +  .5 
3.5   +2 
3.51  +1.5 
2.5    +  .5 

3  |  +1.5 

+1.5 
+2.5 


Collar- 
ette. 


+3.5! 

+2 

+2 


10-10 
11-12 
12-13 


0-7 

Mi 

M 

7-6     10-11 

7-8!     10-11 

6-6 

8-8 


13-13 
12-12 
12-13 


11-12 
10-  9 


i  All  measurements  made  in  \ 

*  Per  cent  of  posterior  fin  in  front  of  tail-septum. 

Distribution. — S.  pulchra  was  collected  from  23  stations,  or  from 
exactly  50  per  cent  of  those  at  which  chaetognaths  were  taken.  Of 
these  only  5  were  mesoplanktonic  stations,  and  14  of  the  remaining 
18  were  surface  stations.  There  can  be  no  question,  therefore,  that 
the  species  is  typical  of  the  upper  epiplankton  in  the  Philippine  region. 
Its  northernmost  record  of  capture  during  the  Philippine  expedition 
is  in  the  China  Sea,  near  Hongkong,  20°  58'  north  and  120°  3'  east; 
its  southernmost  record  is  in  Buton  Strait,  5°  36.1'  south  and  122° 
7.6'  east;  its  easternmost  record  is  in  the  Gulf  of  Tomini,  Celebes, 
125°  17.1'  east  and  1°  13.2'  north;  and  its  westernmost  record  is  in 
Macassar  Strait,  118°  50'  east  and  2°  19.5'  south.  The  largest 
number  (128  +  )  was  taken  August  11,  1909,  at  7.49  in  the  after- 
noon by  a  0000  grit-gauze  net  towed  on  the  surface  between  Siquijor 
and  Bohol  Islands,  at  9°  27.5'  north  and  123°  38'  east.  Other 
species  taken  at  the  same  station  are  S.  enflata  (169),  S.  lyra  (85), 
S.ferox  (50),  and  S.  bedoti  (14). 


CHAETOGXATHA   COLLECTED  BY   STEAMER  ALBATROSS.          253 


t 


L  ~    ss*  «s*   ^i  • 

£  ££££££  ~~  £       ££££  ££ 


333333^*       3  g^<N  3  3  3  3  t~  3  3 
030202020202  0202  02020202       O2  02 


a  a  a  a  a  a  a  a  a  a  a  a  a  a  a  s  a  a  a  s  a  a  a 


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254  BULLETIN   100,   UNITED  STATES   NATIONAL  MUSEUM. 

SAGITTA  DECIPIENS  Fowler. 

Plate  35,  fig.  8;  plate  37,  figs.  18,22. 

Sagitta  dedpiens  FOWLER  (1905),  p.  70.— RITTER-ZAHONY  (1911),  p.  27. 
Sagitta  sibogae  FOWLER  (1906),  p.  21. — RITTER-ZAHONY  (1909a),  p.  5. — MICHAEL 
(1911),  p.  74. 

According  to  Ritter-Zahony  (1911,  p.  29),  there  is  "keine  spezi- 
fischen  Unterschiede  in  Fowler's  Diagnosen  und  Abbildungen  der 
beiden  Arten  [8.  dedpiens  und  S.  sibogae]  und  S.  sibogae  weist 
danach — als  alteres  Stadium ! — gegeniiber  S.  dedpiens  eigentlich  nur 
bedeutendre  Dimensionen  und  hohere  Zahlen  fiir  die  Voider-  und 
Hinterzahne  auf." 

Although  the  species  is  represented  in  the  Philippine  collection 
by  more  than  100  specimens,  few  are  well  enough  preserved  to  permit 
accurate  measurements  and  their  identification  is  therefore  not 
certain.  They  have  more  anterior  and  posterior  teeth  than  recorded 
by  Fowler  (1905,  p.  70)  in  his  original  description,  8  to  11  anterior 
and  19  to  22  posterior  teeth  against  his  records  of  5  to  10  anterior  and 
12  to  18  posterior  teeth.  They  agree,  however,  with  his  (19,06,  p.  21) 
records  for  S.  sibogae,  in  which  the  anterior  teeth  number  7  to  10  and 
the  posterior  teeth  13  to  23.  They  also  agree,  not  so  well  perhaps, 
with  Ritter-Zahony's  (1911,  p.  28)  records.  He  gives  the  number 
of  anterior  teeth  as  7  to  9  and  the  number  of  posterior  teeth  as  12  to 
20.  The  species  is  redescribed  on  the  basis  of  the  Philippine  material. 

Collarette  (pi.  35,  fig.  8)  inconspicuous,  varying  in  length  from 
slightly  less  than  one-quarter  to  slightly  more  than  half  the  body 
width.  Body  flabby,  seldom  retaining  its  form  well,  and  widest  on 
level  with  posterior  end  of  anterior  fins)  tapering  gradually  toward 
head  and  tail.  No  constriction  at  tail-septum.  Ovary  short,  not 
extending  beyond  anterior  limit  of  posterior  fins.  Corona  ciliata 
not  observed. 

Anterior  fins  (pi.  35,  fig.  8)  rayless  throughout  anterior  half, 
longer  and  narrower  than  posterior  fins,  and  extending  slightly 
beyond  posterior  end  of  ventral  ganglion.  Interval  from  anterior 
to  posterior  fins  about  equal  to  maximum  width  of  body. 

Posterior  fins  (pi.  35,  fig.  8)  rayless  in  anterior  extremity.  They 
never  extend  posteriorly  to  seminal  vesicles,  the  interval  varying  in 
length  from  about  25  to  110  per  cent  of  the  maximum  body  width. 
More  than  50  per  cent  of  fin  in  front  of  tail-septum,  varying  from  54 
to  65  per  cent.  Form  irregular,  the  position  of  greatest  width  being 
at  or  just  behind  tail-septum. 

Vestibular  ridge  (pi.  37,  fig.  18)  concealed  by  a  thick  cuticle.  It 
is  characterized  by  large  fairly  regular  papillae  extending  internally 
beyond  the  teeth  and  terminating  near  the  mouth.  Whig  covers 
all  except  the  first  one  or  two  teeth,  the  notch  extending  to  the 
third  or  fourth.  External  process  not  observed.  According  to 


CHAETOGNATHA   COLLECTED  BY   STEAMER  ALBATEOSS. 


255 


Fowler  (1905,  p.  70)  it  is  "a  very  strong  process;  sometimes  forked 
at  the  external  edge." 

Anterior  teeth  8  to  11,  short,  broad,  and  diverging  distally.  Pos- 
terior teeth  19  to  22,  longer,  and  more  closely  set  than  anterior  teeth. 

Seizing  jaws  (pi.  37,  fig.  22),  5  to  7.  Point  inserted  slightly  less 
than  one-third  its  height  into  shaft,  with  an  irregular  triangular 
projection  at  the  middle  of  its  base.  Base  of  point  and  top  of  shaft 
converge  toward  edge  of  jaw.  Edge  of  point  and  edge  of  shaft  on  a 
line  with  each  other,  but  back  of  point  and  back  of  shaft  intersect 
each  other,  forming  an  obtuse  angle.  Tip  of  point  slightly  bent 
toward  edge  of  jaw.  Pulp-canal  displaced  slightly  toward  back  of 
shaft,  with  a  swollen  place  below  base  of  point.  Pulp  evenly  dis- 
tributed throughout  canal. 

TABLE  9. — Measurements  of  Sagitta  decipiens.1 


§ 

1 

I 

Posterior  fin. 

Anterior  fin. 

Collarette. 

1 

.c 

j 

! 

& 

1 

4 

| 

1 

fe 

I 

UIUIUl 

1 
"3 

1 

1 

•s 

1 

"a 

| 

a 

<C3 

I 

1 
1 

1 
J 

"5 

•5 

*o 

_2 

S 

A 

£ 

3 

tl 

5 

fl 

§** 

I 

•S, 

.g 

g 

S3 

§ 

ji 

A 

j§ 

s 
fc 

1 

3 
^ 

1 

I 

s 

1 

2 
£ 

1 

g 

S 

2 
^ 

g 

I 

g 

i, 

fc 

| 

1 

2 

12.4 
12.2 

5.0|  23.5 
5.5   24 

70.5     7.0:  20.0 
67    1    9.5   20.5 

4.0 
5 

5.5 

4.5 

7.5 
6 

64.5 
fi5 

27.0 

98 

1.5 

2.5 

+1.0 

+  1.5 

3.0 
3 

15.5 
15.5 

9-8 
9-9 

19-20 
21-20 

6-« 

6-6 

3 

11 

5.5!  25 

72.5     8.5   21.5 

4.5 

1  5 

4 

5S  5 

W 

2    (+1.5 

1.5 

13 

10-11 

22-22     5-5 

4 

9.1  (?) 

?5.  5 

70    i    8.5   24 

5 

2.5 

4.5 

55 

27 

2.5   +1.5 

1.5 

14 

11-1C 

19-21     7-7 

5 

8.8 

5 

24 

69.5 

8 

22.5 

(?) 

2.5 

3 

58 

28 

2 

+2 

1.5 

15.5       9-8 

20-21 

6-6 

1  All  measurements  made  in  per  cent  of  total  length  of  animal. 
*  Per  cent  of  posterior  fin  in  front  of  tail-septum. 

Distribution. — 8.  decipiens  was  collected  from  only  six  stations, 
four  of  which  were  mesoplanktonic  and  two  surface  stations. 
According  to  the  literature  the  species  is  typically  mesoplanktonic, 
only  the  very  young  having  been  taken  above  100  fathoms.  Its 
records  of  occurrence  during  the  Philippine  expedition  are  given  in 
Table  10. 

SAGITTA  BEDOTI  Bgraneck. 

Plate  35,  fig.  6;  plate  37,  figs.  20, 24;  plate  38,  fig.  30. 

Sagitta  bedoti  BERANECK  (1895),  p.  137.— FOWLER  (1906),  pp.   6-8.— RITTER- 
ZAHONY  (1911),  p.  20.— MICHAEL  (1911),  p.  75. 

According  to  Fowler  (1906,  p.  6)  8.  bedoti  has  "a  very  slight 
thickening  of  the  epidermis  at  the  neck,  but  no  real  collarette." 
In  my  1911  report  those  species  not  taken  from  the  San  Diego 
region  were  briefly  described  and,  not  having  seen  S.  bedoti,  I  as- 
sumed Fowler's  statement  to  be  correct  and  placed  this  species 
among  those  in  which  the  collarette  was  absent.  Subsequently, 
however,  Kitter-Zahony's  (1911)  report  appeared  in  which  he  (p.  20) 


256 


BULLETIN  100,  UNITED  STATES  NATIONAL  MUSEUM. 


II 

So1 


aasa 


a  B  a  a  a  a 


'ZKttK'Z, 


says:  "Collerette  relativ  kurz,  nur  bis  etwa 
zur  halben  Corona  reichend."  The  speci- 
mens collected  during  the  Philippine  expedi- 
tion agree  with  Ritter-Zahony's  statement. 
Every  specimen  has  a  collarette  which, 
while  narrow  and  short,  is  broader  and  longer 
than  that  of  S.  bipunctata.  Owing  to  this 
confusion  in  the  literature,  S.  ledoti  is 
redescribed  from  the  Philippine  speci- 
mens: 

Collarette  (pi.  38,  fig.  30)  conspicuous  but 
short,  extending  caudally  a  distance  nearly 
equal  to  greatest  width  of  body.  Head 
small.  Lateral  fields  large.  Muscles  strong, 
but  narrow.  Body  firm,  retaining  its  form 
well,  widest  slightly  behind  its  middle,  and 
tapering  gradually  toward  head  and  more 
rapidly  toward  tail.  No  constriction  at 
tail-septum.  Tail  20  to  30  per  cent  of  total 
length  of  animal.  Corona  ciliata  not  ob- 
served. 

Anterior  fins  (pi.  35,  fig.  6)  longer  and 
narrower  than  posterior  fins,  without  rays 
in  the  anterior  half  or  two- thirds.  Fins 
extend  nearly  if  not  quite  to  posterior  end 
of  ventral  ganglion,  the  exact  limit  being 
difficult  to  determine  owing  to  absence  of 
rays.  In  some  individuals  the  fins  may 
extend  beyond  posterior  end  of  ganglion, 
but  never  to  its  anterior  end.  Form  acutely 
triangular,  the  position  of  greatest  width 
being  in  posterior  quarter  of  fins. 

Posterior  fins  (pi.  35,  fig.  6)  extend 
caudally  to  seminal  vesicles.  Rays  absent 
in  anterior  extremity.  Usually,  but  not 
always,  less  than  50  per  cent  of  fin  in 
front  of  tail-septum,  the  extremes  being 
40  and  52  per  cent.  Triangular  in  form, 
the  position  of  greatest  width  behi'j;  behind 
tail-septum.  Interval  from  anterior  to 
posterior  fins  varies  from  hah'  to  twice  the 
maximum  width  of  body. 

Vestibular  ridge  (pi.  37,  fig.  2o)- promi- 
nent and  provided  with  regular  and  un- 
usually acute  papillae.  Number  of  papillae 


CHAETOGNATHA  COLLECTED  BY  STEAMER  ALBATROSS. 


257 


less  than  number  of  teeth.  Wing  of  ridge  covers  all  except  the 
first  and  occasionally  the  second  tooth.  Notch  extends  to  the 
fourth  or  fifth  tooth.  External  process  short  and  blunt,  not,  as 
described  by  Fowler  (1906,  p.  6),  "terminating  externally  in  a  well- 
marked,  rather  sharp  process."  Its  length  is  about  two-sevenths 
that  of  entire  ridge. 

Anterior  teeth  8  to  10  and  posterior  teeth  (pi.  37,  fig.  20)  20  to  28 
in  number  in  individuals  10  to  15  mm.  long.  Anterior  teeth  are 
closely  set  and  diverging  distally,  while  the  posterior  teeth  are  more 
closely  set  and  only  slightly  divergent  distally. 

Seizing  jaws  (pi.  37,  fig.  24)  5  to  7  in  number.  Points  with  curved 
tip,  oval  bases,  and  embedded  about  25  per  cent  of  then-  heights 
into  shaft.  Base  of  point  and  top  of  shaft  parallel.  Pulp-canal 
central,  extending  into  point  about  75  per  cent  of  its  height  and 
converging  markedly  toward  edge  of  point.  Pulp  evenly  distributed 
throughout  canal. 

TABLE  11. — Measurements  of  Sagitta  bedoti.1 


i  S 


°   I 


29  0 
25 

25 

25.  r. 

25 
20 

25. 

eg 


24.7  4.0 

24  4.5 

27  3 

23.5  4 
26 


14.4 
16 
14.5 
,  15 
14 
16 
15.5 
16.5 
16.5 
15.5 


9-10 
9-9 
9-10 
S-9 


24-22 
24-23 
27-28 
22-21J 
24-25! 
25-24 
22-21 
24-25 
23-22i 

20-21; 


1  All  measurements  made  in  per  cent  of  total  length  of  animal. 

2  Ter  cent  of  posterior  fin  in  front  of  tail-septum. 

Distribution. — S.  ~bedoti  was  collected  from  only  four  stations,  352 
specimens  having  been  obtained.  As  shown  by  the  following  table 
all  specimens  were  taken  from  the  upper  epiplankton.  This  indica- 
tion that  the  species  typically  occurs  near  the  surface  is  supported 
by  other  expeditions  and  collections.  It  has  been  taken  near  the 
surface  in  the  region  of  Port  Natal  by  the  Gauss  expedition;  in  the 
Maldive  and  Laccadive  Archipelagoes  by  Doncaster  (1902)  under  the 
name  S.  polyodon;  in  the  Malay  Archipelago  by  Beraneck  (1895) ; 
in  the  Siboga  region  by  Fowler  (1906) ;  in  Misaki  Harbor,  Japan,  by 
Aida  (1897)  under  the  name  S.  lipunctata;  and  in  Sharks  Bay, 
Australia,  by  Ritter-Zahony  (1910).  Altogether,  the  evidence  war- 
rants concluding  that  S.  'bedoti  is  characteristic  of  the  upper  epi- 
plankton of  the  tropical  Indo-Pacific  region. 


258 


BULLETIN   100,  UNITED  STATES   NATIONAL  MUSEUM. 


' 


•s. 


SAGITTA  NEGLECTA  Aida. 

Plate  35,  fig.  9. 

Sagitta  neglecta  AIDA  (1897),  p.  16. — FOWLER  (1906),  p.  15. — 
RITTER-ZAHONY  (1911),  p.  23.— MICHAEL  (1911),  p. 
46. 

This  species  is  represented  by  approximately  425. 
specimens  (Cat.  No.  17927,  U.S.N.M.),  many  of  which 
are  mature.  Curiously  enough,  all  were  taken  by  a 
single  surface  haul  on  November  22,  1909,  in  Molucca 
Passage  at  station  D.  5615,  0°  32.5'  south  and  126° 
31.5'  east.  Certain  specimens  obtained  from  five  or 
six  other  stations  were  at  first  thought  to  be  8.  neglecta, 
but  closer  examinations  proved  them  to  be  either 
young  8.  serratodentata  or  8.  ledoti. 

As  in  so  many  other  cases,  the  Philippine  specimens 
have  more  anterior  and  posterior  teeth  than  those 
described  from  the  San  Diego  region.  In  my  former 
(1911,  p.  48)  report,  the  number  of  anterior  teeth  is 
given  as  3  to  5  and  the  posterior  teeth  as  8  to  1 1  in  in- 
dividuals between  8  and  13  mm.  in  length.  The 
Philippine  specimens,  however,  are  smaller,  ranging 
as  a  rule  between  6.5  and  8  mm.  and  the  number  of 
anterior  arid  posterior  teeth  are  4  to  8  and  12  to  16, 
respectively.  This  agrees  better  with  Fowler's  (1906, 
p.  16)  records  for  specimens  from  the  Siboga  region. 
He  records  3  to  7  anterior  and  7  to  15  posterior 
teeth  in  individuals  between  5  and  10  mm.  in  length. 
Similarly,  Ritter-Zahony  (1911,  p.  24)  records  5  to  7 
anterior  and  11  to  18  posterior  teeth  in  individuals 
from  Port  Natal  between  6  and  7.5  mm.  in  length. 
TABLE  13. — Measurements  of  Sagitta  neglecta.1 


18 

28 

37.5 

47 

57 

67 

77 

87 


5.f>:',2 


Posterior  fin. 


Anterior  fin 


25 
23.52 


22.52.5 
2 


40 
10 

37.520.52 
24 


24 


2.5 


All  measurements  made  in  per  cent  of  total  length  of  animal. 
1  Per  cent  of  posterior  fin  in  front  of  tail-septum. 


CHAETOGNATHA  COLLECTED  BY   STEAMEE  ALBATEOSS.          259 
SAGITTA  FEROX  Doncaster. 

Plate  35,  fig.  7;  plate  37,  figs.  21,  25. 

Sagitta  ferox  DONCASTER  (1902),  p.  212.— FOWLER  (1906),  p.  10.— MICHAEL  (1911), 
p.  74. 

Sagitta  robusta  (part)  RITTER-ZAHONY  (1909a),  p.  49;  (1911),  p.  16. 
Kitter-Zahony  (1909a,  1911)  synonymises  this  species  to  S.  ro- 
busta Doncaster  and  says  (1909a,  p.  49):  "Ich  glaube  daher  nicht 
fehlzugehen,  wenn  ich  mich  fur  die  schon  von  Doncaster  (1902, 
p.  212)  als  moglich  hingestellte  Identitat  dieser  beiden  Arten  auspreche 
und  S.  ferox  nur  eine  altere  S.  robusta  auffasse."  Yet,  although  the 
two  species  closely  resemble  each  other,  the  Philippine  specimens 
do  not  indicate  the  slightest  convergence  with  age  in  three  important 
differential  characters  (see  Table  14): 

1 .  The  collarette  is  much  wider  in  8.  ferox  and  nearly  always  extends 
beyond  the  anterior  end  of  the  ventral  ganglion,  while  in  S.  robusta 
it  never  extends  much  over  halfway  from  neck  to  ventral  ganglion. 

2.  Anterior  fins  always  extend  beyond  posterior  end  of  ventral 
ganglion  in  S.  ferox,  while  in  S.  robusta  there  is  an  interval  between 
the  fins  and  ganglion. 

3.  Anterior  fins  are  longer  than  posterior  fins  in  S.  ferox,  while  the 
posterior  fins  are  the  longer  in  S.  robusta. 

These  three  persistent  differences  justify  considering  S.  ferox 
valid  until  critical  study  of  variations  in  these  particulars  can  be 
made.  The  species  is  therefore  redescribed  from  the  Philippine 
specimens  in  hopes  that  this  description  may  aid  in  establishing 
its  valid  or  synonymical  position: 

Collarette  (pi.  35,  fig.  7)  long  and  broad,  extending  past  anterior 
end  of  ventral  ganglion  onto  anterior  fins.  Head  large.  Lateral 
fields  small.  Body  firm,  opaque,  and  nearly  of  uniform  width  from 
in  front  of  ventral  ganglion  to  tail-septum.  Tail  25  to  30  per  cent 
of  total  length  of  animal.  Corona  ciliata  not  observed. 

Anterior  fins  (pi.  35,  fig.  7)  longer  and  slightly  narrower  than 
posterior  fins,  always  extending  anteriorly  beyond  posterior  end  of 
ventral  ganglion,  frequently  past  its  middle  and  occasionally  to  its 
anterior  end.  Form  acutely  triangular,  the  position  of  greatest 
width  being  in  posterior  quarter  of  fin. 

Posterior  fins  (pi.  35,  fig.  7)  extend  caudally  to  seminal  vesicles. 
Interval  from  anterior  to  posterior  fins  3  to  7,  usually  about  5  per 
cent  of  total  length  of  animal.  Less  than  50  per  cent  (41  to  44)  of 
fin  in  front  of  tail-septum.  Triangular  in  form,  the  position  of 
greatest  width  being  about  midway  between  tail-septum  and  seminal 
vesicles. 

Vestibular  ridge  (pi.  37,  fig.  21)  strongly  mamillated,  the  number 
of  papillae  corresponding  to  the  number  of  teeth.  Wing  of  ridge 
covers  all  except  the  first  two  teeth,  the  notch  extending  beyond 
the  fourth  or  fifth.  External  process  short,  broad,  and  blunt. 


260 


BULLETIN  100,  UNITED  STATES  NATIONAL  MUSEUM. 


Anterior  teeth  5  to  9  in  number.  They  are  closely  set,  provided 
with  broad  bases,  and  diverging  distally. 

Posterior  teeth  (pi.  37,  fig.  21)  10  to  14  in  number.  They  are  long, 
broad,  closely  set,  and  diverging  distally. 

Seizing  jaws  (pi.  37,  fig.  25)  4  to  6  in  number.  Point  with  an 
oval  base  inserted  into  shaft  between  15  and  20  per  cent  of  its  height. 
Base  of  point  and  top  of  shaft  converge  toward  back  of  shaft.  Edge 
of  shaft  provided  with  narrow  crest.  Pulp-canal  central,  and  extend- 
ing into  point  about  80  per  cent  of  its  height.  Pulp  evenly  dis- 
tributed throughout  canal. 

TABLE  14. — Measurements  of  Sagittaferox.1 


Posterior  fin. 


Anterior  fin. 


+3.5 
+4 
+4 
+5.5 


Collarette. 


+3 

+2 

+1 

+2 

+3.5 

+4 


+3 


13-13 
12-11 


13-13  6-5 

13-12  5-5 

13-14  5-4 

15-12  I  5-6 

12-12  5-4 

12-12  ;  5-5 

12-12  5-1 

12-12  '  5-5 

12-?  5-5 

10-12  5-5 


i  All  measurements  made  in  per  cent  of  total  length  of  animal. 

1  Per  cent  of  posterior  fin  in  front  of  tail-septum. 

»  The  +  indicates  that  the  fin  extends  beyond  posterior  end  of  ganglion. 

« The  +  indicates  that  the  collarette  extends  beyond  anterior  end  of  ganglion. 

Distribution. — 8.  ferox  was  collected  from  22  of  the  46  stations 
from  which  chaetognaths  were  taken,  598  specimens  being  obtained. 
It  is  difficult  to  decide  whether  the  species  is  typically  epiplanktonic 
or  mesoplanktonic  in  the  Philippine  region.  At  15  stations  it  was 
taken  from  above  100  fathoms.  Five,  or  33  per  cent  of  the  epiplank- 
tonic hauls,  and  two,  or  29  per  cent  of  the  mesoplanktonic  hauls, 
obtained  more  than  the  average  number  of  specimens  (27).  Again, 
the  median  number  of  those  taken  above  100  fathoms  is  nine,  but 
nine  is  also  the  median  number  of  those  taken  below  100  fathoms. 
Finally,  the  greatest  number  was  taken  from  25  fathoms,  the  second, 
fhird,  and  fourth  greatest  from  the  surface,  and  the  fifth  greatest 
trom  500  fathoms. 

All  subsurface  hauls,  however,  were  made  by  various  types  of  open 
nets.  It  is  well  to  remember  that  such  hauls,  whether  horizontal  or 
vertical,  afford  no  certain  evidence  of  the  depth  from  which  specimens 


CHAETOGNATHA  COLLECTED  BY   STEAMER  ALBATBOSS.          261 

were  collected.  This  is  true  even  when  every  haul  is  made  with  the 
same  net,  and  when  various  types  of  nets  are  used  the  data  are  worse 
than  useless  for  this  purpose.  For  these  reasons  it  may  well  be 
that,  as  indicated  by  other  reports,  S.ferox  is  typically  epipianktonic 
in  the  Philippine  region.  It  was  taken  in  abundance  during  the 
Siboga  expedition  from  the  surface,  but  only  rarely  from  the 
mesoplankton. 

Indeed  the  species  appears  to  be  restricted  to  the  epiplankton  of 
the  Indo-Australian  region,  although,  owing  to  its  questionable 
synonymy  with  S.  robusta  Doncaster,  this  statement  is  made  with 
some  reservations.  But,  even  assuming  the  two  species  to  be  synony- 
mical,  it  is  still  restricted  in  distribution  to  the  surface  and  upper 
epiplankton  of  tropical  and  subtropical  regions.  Thus,  according 
to  Ritter-Zahony  (1911,  p.  58),  it  is  found  "im  Atlantischen  Ozean 
zwischen  0°  and  20°  N.,  im  Indischen  zwischen  20°  and  30°  S.  in 
Vertikalfangen  und  an  der  Oberflasche.  ..."  He  continues: 
"Auf  der  Westseite  des  Atlantischen  Ozeans  wird  sie  zwar  durch 
den  Floridastrom  wohl  bis  in  die  Gegend  des  40°  N.  gebracht,  auf 
der  Ostseite  gelangt  sie  jedoch  kaum  bis  zum  35°.  Breitegrad,  da 
sie  ja  schon  im  Mittelmeer  fehlt.  Im  Siiden  diirfte  sie  gerade  noch 
um  die  Siidspitze  Afrikas  herumkommen.  Im  Stillen  Ozean  ist 
sie  bisher  nur  funf  Fundorten,  die  samtlich  auf  seiner  Westseite 
liegen,  bekannt  geworden.  .  .  .  Ich  glaube  jedoch,  dass  die  Ver- 
breitung  der  S.  robusta  im  Stillen  Ozean  der  im  Atlantischen  vollig 
analog  ist,  d.  h.  das  tropisch-subtropische  Gebeit  umfasst  und  nur 
auf  der  Westseite  etwas  weiter  nach  Norden  reicht,  wobei  der  Kuro- 
Siwo  die  Rolle  des  Floridastroms  uberniinmt."  Clearly  S.  ferox 
is  a  warm  water  species,  but  is  its  absence  hi  the  eastern  Pacific 
not  more  likely  attributable  to  the  abnormally  cold  water  there 
due  to  upwelling?  (see  p.  271). 

The  northernmost  and  westernmost  record  of  its  capture  in  the 
Philippine  region  is  21°  31'  north  and  117°  53'  east,  or  in  the  south 
China  Sea,  approximately  halfway  between  the  city  of  Hongkong 
and  the  island  of  Formosa.  The  southernmost  record  is  5°  36' 
south  at  122°  7.6'  east  off  the  south  end  of  the  island  of  Celebes  in 
Buton  Strait.  The  easternmost  record  is  0°  32.5'  south  and  126° 
31.5'  east,  or,  less  accurately,  at  the  southern  end  of  Molucca  Passage 
east  of  Tomini  Bay.  The  largest  number  of  specimens  (217)  was 
taken  February  7,  1908,  at  8.05  in  the  morning,  from  25  fathoms  by 
an  open  0000  grit-gauze  net  towed  horizontally  9  fathoms  above  the 
bottom  of  the  Sulu  Archipelago,  near  Basilan  Island,  at  6°  44.2' 
north  and  121°  47'  east.  The  other  records  are  given  in  the  table 
following. 


262  BULLETIN   100,   UNITED  STATES   NATIONAL  MUSEUM. 


i§S    o  S3    c* 

i-«  F-i        00  t^        O 


•ssss«§M 

^>S  a^o^ 

-s-sS&Bsi 


<N  M  <N  S  »-«  <N 


^gaccoccoooM-o 


CKAETOGJSTATHA   COLLECTED  BY   STEAMER  ALBATEOSS. 


263 


SAGITTA  PLANKTONIS  Steinhaus. 

Sagitta  planktonis  STEINHAUS  (1896),  p.  39. — RITTER-ZAHONY  (1911),  p.  29. — 

MICHAEL,  (1911),  p.  44. 
Sagitta  zetesios  FOWLER  (1905),  p.  67;  (1906),  p.  22. 

Eighty-seven  specimens  were  obtained,  but  unfortunately  all  except 
one  were  preserved  in  alcohol,  with  the  result  that  they  are  so  badly 
distorted  as  to  prevent  certain  identification.  Measurements  of  the 
single  well-preserved  specimen  are: 

Length 27      mm. 

Width 8.  5  per  cent  of  length. 

Tail: 

Length 24.  5  per  cent  of  length. 

To  central  ganglion 68.  0  per  cent  of  length. 

Ventral  ganglion  (length) 4.  0  per  cent  of  length. 

Posterior  fin: 

Length 20.  5  per  cent  of  length . 

Width 4.  5  per  cent  of  length. 

To  anterior  fin 4.  5  per  cent  of  length. 

Proportion  in  front  of  tail-septum 77.  0  per  cent. 

Anterior  fin : 

Length '. 23.  0  per  cent  of  length. 

Width 2.  5  per  cent  of  length. 

To  ventral  ganglion 0.  0  per  cent  of  length. 

Collarette: 

Length 25. 0  per  cent  of  length. 

To  ventral  ganglion ' 0. 0  per  cent  of  length. 

Number  of  anterior  teeth 8-7 

Number  of  posterior  teeth 17-18 

Number  of  seizing  jaws 8-8 

The  length,  number  of  anterior  and  posterior  teeth,  and  number  of 
seizing  jaws  of  a  few  other  individuals  are: 


Length  in 
mm. 

Anterior 
teeth. 

Posterior 
teeth. 

Seizing  jaws. 

11.5 
13 
16.5 
17 
21 
25 

7-6 
9-9 
9-10 
10-9 
8-8 
9-8 

13-12 
16-? 
16-15 
17-18 
16-17 
18-17 

9-8 
7-8 
9-9 
8-8 
8-8 
8-9 

The  number  of  teeth  is  greater  than  in  specimens  from  the  San 
Diego  region  (Michael,  1911,  p.  45).  San  Diego  specimens,  ranging 
in  length  between  15  and  26  mm.,  have  4  to  7  anterior,  and  11  to  15 
posterior  teeth.  In  the  Biscayan  report,  however,  Fowler  (1905,  p. 
68)  records  a  variation  in  number  of  anterior  teeth  from  5  to  9  and  of 
posterior  teeth  from  11  to  19  in  individuals  between  11  and  21  mm. 
in  length. 

Distribution. — 8.  planktonis  was  collected  from  only  seven  stations. 
Of  the  84  specimens  obtained,  53  were  taken  from  below  100  fathoms 
by  open  nets  towed  horizontally  at  four  stations  for  approximately 


264  BULLETIN  100,  UNITED  STATES  NATIONAL  MUSEUM. 


1 


a  s  a  a  a  a  a  a  a 

a  d  P.  a  cs  os  d 


20  minutes  at  each.  The  35  remaining 
specimens  were  taken  from  above  15 
fathoms  at  the  three  remaining  stations 
by  20-minute  tows.  These  facts  in- 
dicate that  the  species  is  typically 
mesoplanktonicin  the  Philippine  region, 
which  indication  is  supported  by  the 
results  of  many  other  expeditions.  In 
the  regions  covered  by  the  Biscayan, 
Siboga,  and  Plankton  expeditions,  as 
well  as  off  the  California  coast,  the 
species  occurs  abundantly  below  100 
fathoms,  but  is  rarely  found  above  that 
depth.  It  is  common  between  500  and 
1,000  fathoms,  and,  as  Ritter-Zahony 
(1911,  p.  62)  says:  "S.  planktonis  ist 
unter  alien  Arten  der  Tiefsee  am  hau- 
figste/i  in  der  Literatur  erwahnt." 

Genus  PTEROSAGITTA  Costa. 

Syn.  Spadella  LANGERHANS  (part  1). 

PTEROSAGITTA  DRACO  (Krohn). 

Plate  36,  figs.  11, 12, 13. 
Sagitta  draco  KROHN  (1853),  p.  273. 
Pterosagitta  mediterranea  COSTA  (1869),  p.  55. 
Spadella    draco    FOWLER    (1906),    p.   25. — 

MICHAEL  (1911),  p.  54. 
Pterosagitta  draco    RITTER-ZAHONY  (1911), 

p.  33. 

Thirty-two  specimens  were  obtained, 
of  which  only  one  has  mature  ovaries. 
These  completely  fill  the  body  cavity 
(pi.  36,  fig.  13),  extending  from  tail- 
septum  to  neck.  All  other  specimens 
are  clearly  immature,  and  in  nearly 
one-half  there  is  no  trace  of  ovaries, 
and  the  seminal  vesicles  are  barely 
visible  (pi.  36,  fig.  12).  Fowler  (1906, 
p.  26)  records  the  tail  as  41  to  57  per 
cent  of  total  length  in  specimens  be- 
tween 6  and  9  mm.  The  Philippine 
specimens,  however,  vary  only  between 
39.5  and  44.3  per  cent.  Otherwise 
Fowler's  records  agree  exceptionally 
well  with  the  Philippine  material. 
He  records  7  to  9  seizing  jaws,  7  to 


CHAETOGKATHA   COLLECTED  BY   STEAMER  ALBATROSS. 


265 


10  anterior  teeth,  and  11  to  16  posterior  teeth;  the  Philippine  speci- 
mens show  7  to  9  seizing  jaws,  6  to  10  anterior  teeth,  and  10  to  16 
posterior  teeth. 

Nearly  half  the  Philippine  specimens  are  devoid  of  the  collarette, 
except  for  a  narrow  strip  behind  the  head.  This  caused  consider- 
able trouble  in  identification  until  others  were  discovered  in  which 
the  structure  was  partly  missing.  These  (pi.  36,  figs.  12  and  13) 
indicate  that  for  some  unknown  reason  the  collarette  has  been  torn 
off.  Immature  specimens  in  this  condition  bear  a  striking  super- 
ficial resemblance  to  young  S.  jerox. 

TABLE  17. — Measurements  of  Pterosagitta  draco.1 


Number. 

Length  in  mm. 

Width  with  colla- 
rette. 

Width  without 
collarette. 

Length  of  tail. 

sl 

I 

Length  of  ventral 
ganglion. 

Lateral  fin. 

Ovary. 

Number  of  ante- 
rior teeth. 

| 
ol 

ji 

Number  of  seizing 
jaws. 

a 

i 

"6.T 
5.7 

6.8 
5 

"i'e" 

6.3 
5.7 
5.3 
4.8 
6.1 
5.5 
4.8 
5.6 
6.5 
5.8 
5.3 
4.8 

It 

£° 

43 

& 

1 

5 

1 

2 
3 
4 

7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 

7.7 
7.6 
7.4 
7.2 
7 
6.9 
6.9 
6.7 
6.7 
6.6 
6.6 
6.3 
5.8 
5.8 
5.6 
5.4 
5.4 
5.3 
5.1 
4.9 

7.8 
6.9 
7.1 
10.7 
8 
7.6 
6.6 
6.8 
7.8 
8.5 
7.4 
7.3 
7.9 
7.9 

S:i 

7.8 
6.7 
6.2 
7.1 

43.3 
44 

42.8 
39.5 
44 
40.3 
43.1 
41.4 
40.5 
40.9 
42 
41.3 
40 
42.3 
41.6 
42.5 
40.8 
41.3 
41.4 
44.3 

66.6 

66.5 
65.6 
59.6 
66.9 
65.2 
66.5 
65 
64 
62.7 
65 
64.8 
63.6 
66.7 
66.5 
65.5 
64.2 
64.5 
64.9 
68.5 

9.1 
8.7 
9.1 
7.8 
8.5 
9.2 
8.1 
10 
9.9 
10.6 
9.6 
9.5 
9.7 
6.7 
8.7 
9.8 
9.7 
10.7 
11 
10.7 

22.8 
23.4 
22.4 
20 
23 
23 
22.3 
23.1 
21.3 
21.8 
19.1 
22.9 
21.8 
18.8 
16.8 
20.2 
20.8 
22.7 
20.7 
21.4 

0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 

o 

24.6 
24.8 
25.7 
47.8 
21 
10.7 
20.8 
9.5 

2.3 
2.7 
1.9 
5.9 
4.5 
.5 
1.5 
1 

9-8 
9-8 
9-8 
5-6 
8-7 
7-6 
8-8 
8-7 
10-9 
7-7 
6-6 
9-8 
6-7 
9-8 
8-7 
8-7 
7-7 
7-7 
6-6 
7-6 

13-13 

(?)-14 
15-16 
11-12 
14-13 
14-(?) 
13-13 
13-14 
15-(?) 
14-15 
11-12 
14-(?) 
11-11 
14-14 
12-11 
14-15 
(?)-H 
10-11 
11-12 
13-13 

8-7 
8-8 
8-9 
8-8 
8-9 
8-9 
8-8 
8-8 
8-8 
8-8 
9-9 
8-8 
9-9 
8-9 
9-8 
8-9 
7-7 
8-8 
(?)-8 
7-7 

16.6 
15.2 

"ie.Y 

13 
13.3 

"isT 
...5... 

........ 

10.4 

6.8 

1.1 

"is"" 

"5"" 

1  All  measurements  made  in  per  cent  of  total  length  of  animal. 

Distribution. — P.  draco  was  obtained  from  only  five  stations,  all 
of  which  were  subsurface  ones.  Two  were  mesoplanktonic,  but  they 
only  yielded  four  specimens.  The  remaining  28  were  obtained  from 
between  the  surface  and  25  fathoms,  indicating  that  hi  so  far  as  the 
species  occurs  in  the  Philippine  region  it  is  typical  of  the  upper  epi- 
plankton.  This  accords  with  what  is  known  of  its  distribution  gen- 
erally. Although  nowhere  abundant  it  is  apparently  restricted  to 
the  upper  epiplankton  of  tropical  and  subtropical  regions.  Says 
Ritter-Zahony  (1911,  p.  63):  "Ihre  Verbreitung  diirfte  sich  mit  der 
von  S.  enflata  und  'bipunctata  decken,  doch  ist  die  Art  in  den  gemassig- 
ten  Zonen,  soweit  sie  iiberhaupt  noch  darin  vorkommt,  schon  seltener 
als  jene  beiden.  .  .  ."  Its  northernmost  and  southernmost  records 
of  occurrence  are  42°  north,  56°  west;  and  42°  south,  36°  east. 
Its  records  of  capture  during  the  Philippine  expedition  are  given  in 
the  table  following: 

59318— 19— Bull.  100 3 


266 


BULLETIN   100,   UNITED  STATES  NATIONAL  MUSEUM. 


*  fc 
«»' 

op 


os^rto 


se- 


f.!l 


iilll 

fifiQOQ 


Genus  EUKROHNIA  Ritter-Zfihony. 

Syn.  Krohnia  LANGERHANS  (part). 

EUKROHNIA  HAMATA  (MSbius). 

Plate  37,  figs.  14,27. 

Sagitta  hamata  MOBIUS  (1875),  p.  158. 

Krohnia  hamata  KRUMBACH  (1903),  p.  639.— FOW- 
LER (1905),  p.  74;  (1906),  p.  23. 

Eukrohnia  hamata  RITTER-ZAHONY  (1911),  p.  39. — 
MICHAEL  (1911),  p.  51. 

This  species  is  represented  by  six  poorly 
preserved  and  badly  damaged  specimens  (Cat. 
No.  17928,  U.S.N.M.).  The  heads  of  all  but 
two  are  missing  and  in  one  of  those  it  is 
torn  away  from  the  body.  It  is  impossible, 
therefore,  to  accurately  determine  the  length 
or  to  count  the  teeth  and  seizing  jaws  in 
four  of  the  six  specimens.  The  other  two 
are  16  and  16.3  mm.  in  length;  their  tails 
are  28.3  and  30.2  per  cent  of  their  lengths; 
the  number  of  teeth  are  21-21  and  24-25, 
and  the  number  of  seizing  jaws  are  9-10 
and  9-9. 

The  number  of  teeth  (pi.  37,  fig.  14)  greatly 
exceed  that  recorded  by  Ritter-Zahony 
(1911,  p.  39)  for  specimens  taken  from  the 
Antarctic  Ocean,  as  well  as  that  recorded 
by  me  (1911,  p.  52)  for  specimens  from  the 
San  Diego  region.  Although  Ritter-Zahony 
records  a  variation  in  number  of  teeth  from 
4  to  23,  he  gives  12  as  the  upper  limit  for 
specimens  under  18  mm.  in  length.  Simi- 
larly, in  specimens  from  the  San  Diego  region 
between  13  and  17.5  mm.  in  length,  I  have 
never  found  more  than  13  teeth.  Fowler 
(1906,  p.  23),  however,  records  22  in  speci- 
mens from  the  Siboga  area  that  are  only  13 
mm.  hi  length.  It  is  evident,  therefore, 
that  the  number  of  teeth  vary  according 
to  the  region  in  which  the  species  occurs. 

The  pouits  of  the  seizing  jaws  (pi.  37,  fig. 
27)  are  curved  to  an  unusual  extent,  and 
the  jaws  are  not  serrated  as  described  by 
Krumbach  (1903).  Otherwise,  however,  the 
structure  of  the  jaws  agree  with  his  de- 
scription. 


CHAETOGNATHA  COLLECTED  BY  STEAMER  ALBATEOSS. 


267 


The  six  specimens  were  all  obtained  November  6,  1908,  in  the 
China  Sea  in  the  vicinity  of  Formosa,  at  station  D.  5320,  20°  58' 
north  and  120°  3'  east  by  an  open  0000  grit-gauze  net  towed  at  3.18 
p.  m.  in  500  fathoms  for  20  minutes. 

EUKROHNIA  RICHARDI  Germain  and  Joubin. 

Plate  36,  fig.  10;  plate  37,  figs.  15,  26. 
Eukrohnia  richardi  GERMAIN  and  JOUBIN  (1912),  p.  2. 

This  species  (pi.  36,  fig.  10)  is  represented  by  five  specimens,  only 
two  of  which  are  well  enough  preserved  to  permit  certain  identifi- 
cation. Measurements  of  these  two  (a  and  6),  and,  for  comparison, 
those  taken  from  Germain  and  Joubin's  drawing  (c),  are  as  follows: 


a. 

b. 

C. 

Length  in  mm  ... 

27.7 

27  8 

27  8 

Width  in  per  cent  of  length  

12.9 

13.3 

12.2 

Tail: 
Length  in  per  cent  of  total  length  

27.2 

26.2 

25.2 

To  ventral  ganglion  in  per  cent  of  total  length 

70  7 

74  2 

67  6 

Length  of  ventral  ganglion  in  per  cent  of  total  length  

6.6 

5.2 

2.9 

Lateral  fin: 

73  1 

69  3 

68  4 

Width  in  per  cent  of  total  length            ...             .... 

4.9 

6  5 

6  5 

Extends  bevond  anterior  end  of  ventral  ganglion,  in  per  cent 
of  total  length  
Proportion  in  front  of  tail-septum  (per  cent)  

10.4 
82.7 

6.5 
86.4 

10.8 
74.4 

Ovary: 

4  g 

6  5 

10  8 

Width  in  per  cent  of  total  length          

1.26 

2.64 

2  88 

22  21 

25-24 

24 

Number  of  seizing  jaws  

10-11 

10-10 

8 

It  is  questionable  whether  this  species  is  valid  or  not.  It  closely 
resembles  E.  hamata,  but  according  to  Germain  and  Joubin  (1912, 
p.  5),  "il  s'en  distingue  facilement,  en  dehors  de  sa  coloration  verte 
caracte"ristique  et  jusqu'a  present  absolument  unique  chez  tous  les 
Chetognathes,  par  la  forme  tres  diff e"rente  de  sa  tfite,  beaucoup  plus 
nettement  triangulaire  allong6e,  par  ses  crochets  plus  e'troitement 
allonges  et  par  ses  dents,  au  nombre  de  24,  alors  qu'on  en  compte 
seulement  de  20  a  22  chez  I' Eukrohnia  liamata"  Of  these  distinc- 
tive features  it  is  evident  that  differences  in  the  number  of  teeth 
and  shape  of  head  are  of  no  specific  value,  and  it  seems  probable 
that  the  color,  which  is  described  (p.  2)  as  "d'un  vert  d'eau  plus 
fonce  a  la  region  ante"rieure  et  s'attenuant  re'gulierement  vers  la 
queue,"  is  also  highly  variable.  In  the  Philippine  material  at  least, 
specimens  of  E.  hamata  agree  quite  as  well  with  this  description  as 
those  of  E.  richardi.  Both,  although  considerably  faded  by  action 
of  the  f  ormalin,  are  dark  green  and  more  so  anteriorly  than  posteriorly. 

Again,  the  various  dimensions  of  the  body  recorded  by  Germain 
and  Joubin  (p.  4)  do  not  agree  with  those  taken  from  the  drawing. 
The  drawing  measures  139  mm.  in  length.  Assuming  the  recorded 
length  of  27  mm.  to  be  accurate,  the  magnification  of  the  drawing 
is  5.15.  This  makes  the  length  of  tail  6.8  mm.,  or  25.2  per  cent  of 


268  BULLETIN  100,  UNITED  STATES  NATIONAL  MUSEUM. 

total  length,  but  it  is  given  as  6.5  mm.,  or  24  per  cent  of  the  total 
length.  It  is  stated  that  the  ovaries  are  2.25  mm.  in  length,  or  8.3 
per  cent  of  the  length  of  animal,  but  in  the  drawing  they  measure 
10.8  per  cent,  which  is  equivalent  to  2.92  mm.  The  maximum  width 
of  body  ("y  compris  la  largeur  des  nageoires")  is  given  as  2.5  mm., 
or  9.3  per  cent  of  the  length  of  animal,  but  in  the  drawing  it  measures 
11.5  per  cent,  which  is  equivalent  to  3.1  mm.  Finally,  it  is  stated 
that  the  lateral  fin  occupies  "17/27  [63  per  cent]  de  la  longeur  totale 
de  1' animal,"  that  it  extends  5.5  mm.  anterior  to  the  ventral  ganglion 
or  "a  environ  3  millimetres  de  Textre'mite'  du  corps,"  but  in  the 
drawing  it  measures  68.4  per  cent  of  the  total  length  of  animal  and 
extends  only  10.8  per  cent,  or  2.92  mm.,  anterior  to  the  ventral 
ganglion. 

Although  these  discrepancies  are,  for  the  most  part,  small,  they 
make  it  impossible  to  depend  with  certainty  upon  either  the  descrip- 
tions or  the  drawing,  and  whether  E.  richardi  is  or  is  not  synonymous 
with  fi.  Jiamata  must  remain  undecided  until  the  type  is  more  accu- 
rately described.  In  spite  of  this  uncertainty  there  are  several 
points  that  indicate  its  validity: 

1.  The  seizing  jaws  (pi.  37,  fig.  26)  are  more  massive  than  those  of 
E.  Jiamata  and  their  points  are  quite  dissimilar.     In  E.  Jiamata  the 
points  are  always  sickle-shaped  (pi.  37,  fig.  27),  although  they  are 
not  usually  curved  so  much  as  in  the  Philippine  material;  the  top 
of  shaft  and  base  of  point  converge  upon  approaching  the  edge  of 
the  jaw;  the  point  has  an  oval  base;  and  the  pulp-canal  is  central 
and  sparsely  filled  with  pulp.     In  E.  richardi,  on  the  other  hand,  the 
points  are  not  sickle-shaped;  the  top  of  shaft  and  base  of  point  are 
parallel;  the  point  has  an  irregular  rather  than  an  oval  base;  the 
pulp-canal  is  irregular  in  outline  and  is  displaced  toward  the  back 
of  shaft;  and  the  pulp  is  evenly  distributed. 

2.  The  body  of  E.  richardi  is  between  two  and  three  times  wider 
in  proportion  to  the  length  of  animal  than  is  the  case  with  E.  Jiamata. 

3.  Lateral  fins  extend  to,  but  rarely  beyond,   anterior  end  of 
ventral  ganglion  in  E.  Jiamata,  while  in  E.  richardi  they  extend 
beyond  the  anterior  end  of  ganglion  by  6  to  11  per  cent  of  the  length 
of  animal. 

4.  Lateral  fins  in  E.  Tiamata  with  "fin-rays  extending  about  as  far 
in  front  of  the  septum  as  the  fin  does  behind  it,  but  the  fin  continued 
forwards  as  an  expansion  of  the  epidermis  up  to  or  to  the  middle  of 
the  ventral  ganglion."     [Fowler  (1905,  p.  74).]     In  E.  richardi  the 
fin,  according  to  Germain  and  Joubin,  is  delicately  rayed  throughout, 
the  rays  making  an  acute  angle  with  the  body  as  illustrated  by  their 
drawing.     This  seems  to  be  true  of  the  Philippine  specimens  (pi.  36, 
fig.   10),  although  the  rays  are  fewer  and  much  finer  toward  the 
anterior  end. 


CHAETOGNATHA  COLLECTED  BY   STEAMER  ALBATROSS.          269 

5.  Lateral  fins  never  extend  more  than  halfway  from  tail-septum 
to  seminal  vesicles  in  E.  Jiamata,  while  they  extend  three-quarters  of 
the  distance,  according  to  Germain  and  Joubin's  drawing,  and  quite 
to  the  anterior  end  of  the  vesicles  in  the  Philippine  specimens. 
.  The  Philippine  specimens  apparently  differ  from  the  type  in  two 
points : 

(1)  Germain  and  Joubin  state  that  the  ventral  neck  muscles  are 
composed  of  longitudinal  fibers,  together  with  very  fine  transverse 
ones.     The  transverse  fibers  are  absent  in  the  Philippine  specimens. 

(2)  The  seminal  vesicles  are  figured  and  described  as  very  small 
disks  lying  within  the  anterior  end  of  the  caudal  fin.     In  the  Phil- 
ippine specimens  this  is  not  the  case,  although  the  vesicles  in  all 
specimens  were  very  immature.     Their  appearance,  however,  sug- 
gests that  when  mature  their  posterior  extremities  may  touch  the 
caudal  fin. 

The  five  specimens  (Cat.  No.  17929,  U.S.N.M.)  were  all  obtained 
at  12.07  in  the  afternoon,  May  8,  1909,  station  D.  5437,  off  the  west 
coast  of  Luzon,  15°  45/9  north  and  119°  42/8  east,  by  an  open 
0000  grit-gauze  net  towed  for  27  minutes  in  450  fathoms. 

Genus  KROHNITTA  Ritter-ZShony. 

Syn.  Krohnia  LANGERHANS  (part). 
Spadella  GRASSI  (part). 
Krohnia  STRODTMAN  (part). 

KROHNITTA  SUBTILIS  (Grassi). 

Spadella  subtilis  GRASSI  (1883),  p.  23. 

Krohnia  subtilis  STRODTMAN  (1892),  p.  22.— FOWLER  (1905),  p.  78;  (1906),  p.  25. 
•  Krohnia  padfica  FOWLER  (1906),  p.  24. 
Eukrohnia  subtilis  MICHAEL  (1911),  p.  52. 
Krohnitta  subtilis  RITTER-ZAHONY  (1911),  p.  44. 

Only  three  specimens  were  obtained,  all  of  which  are  immature. 
Only  one  is  sufficiently  well  preserved  to  permit  accurate  measure- 
ments : 

Length  in  mm 9.8. 

Length  of  tail 35.9  per  cent  of  total  length. 

Tail  to  ventral  ganglion 63.5  per  cent  of  total  length. 

Length  of  ventral  ganglion 7.5  per  cent  of  total  length. 

Length  of  fin •. .  35.1  per  cent  of  total  length . 

Width  of  fin 6.4  per  cent  of  total  length. 

Proportion  of  fin  in  front  of  tail-septum 32.7  per  cent. 

Length  of  ovary 8.6  per  cent  of  total  length- 
Width  of  ovary 2.1  per  cent  of  total  length. 

Number  of  seizing  jaws 8-8. 

The  teeth  could  not  be  counted,  but  in  the  two  other  specimens, 
which  were  about  the  same  length,  the  number  of  teeth  on  the  right 
and  left  sides  are  11-10  in  one  and  12-13  in  the  other  specimen. 
Similarly,  the  number  of  seizing  jaws  are  8-7  in  the  first  specimen 
and  (?)-7  in  the  second. 


270  BULLETIN   100,  UNITED  STATES    NATIONAL   MUSEUM. 

Two  of  the  specimens  (Cat.  No.  17931,  U.S.N.M.)  were  obtained 
between  Panay  and  Negros  at  station  D.  5185,  10°  5/8  north  and 
122°  18/5  east,  on  March  30,  1908,  at  5.26  in  the  afternoon,  by  an 
open  0000  grit-gauze  net  towed  horizontally  for  20  minutes  in  550 
fathoms.  The  third  specimen  (Cat.  No.  17930,  U.S.N.M.)  was 
obtained  in  the  China  Sea  in  the  vicinity  of  Formosa,  at  station 
D.  5319,  21°  31'  north  and  117°  53'  east,  on  November  5,  1908,  at 
7.23  in  the  afternoon,  by  the  same  net  towed  for  27  minutes  in  20 
fathoms. 

COMPARISON    OF   PHILIPPINE   CHAETOGNATHA   WITH   THOSE    FROM 
THE  SAN  DIEGO  REGION. 

Aida  (1897)  describes  10  species  from  Misaki  Harbor,  Japan,  of 
which  all  except  8.  regularis  and  8.  Jiispida  (  =  8.  robusta  Doncaster) 
are  represented  in  the  Philippine  collection.  Again,  Doncaster 
(1902)  records  10  species  from  the  Maldive  Archipelago,  of  which  all 
save  8.  regularis  and  8.  Jiispida  are  present  in  the  Philippine  material. 
Likewise,  Fowler  (1906)  describes  14  species  from  the  "Siboga" 
area,  of  which  all  save  8.  regularis  and  8.  hispida  have  been  taken 
from  the  Philippines.  Lastly,  Bitter-Zahony  (1910)  lists  10  species 
from  Sharks  Bay,  Australia,  of  which  all  except  8.  regularis  and  8. 
bipunctata  are  represented  in  the  Philippine  collection.  The  only 
species  obtained  from  the  Philippines  which  are  not  recorded  from  any 
of  these  regions  are  8.  pJiilippini  and  E.  richardi,  the  former  a  new 
species  represented  by  a  single  individual,  and  the  latter  a  rare 
species  represented  by  only  five  specimens.  Obviously  these  facts 
strongly  point  toward  a  uniformity  in  the  chaetognath  fauna,  espe- 
cially the  epiplankton,  over  the  Indo-Pacific  Ocean,  notwithstanding 
the  curious  absence  of  8.  regularis  and  8.  Jiispida  in  the  Philippine 
collection. 

The  situation  is  quite  otherwise  when  the  Philippine  chaetognatha 
are  compared  with  those  from  the  San  Diego  region,  for  those  species 
most  characteristic  of  the  Philippines  are  those  that  are  either 
absent  or  least  characteristic  of  the  San  Diego  region,  and  the  op- 
posite. Thus,  8.  enflata,  by  far  the  most  typical  and  abundant 
species  about  the  Philippines,  has  been  obtained  in  the  San  Diego 
region  by  less  than  20  out  of  nearly  4,000  hauls.  Conversely,  8. 
bipunctata  is  by  far  the  most  typical  and  abundant  species  in  the 
San  Diego  region,  but  not  a  single  individual  was  obtained  from  the 
Philippines.  Again,  Sagittaferox,  8.  pulcJira,  8.  bedoti,  8.  decipiens,  8. 
minima,  8.  macrocephala,  and  Eukrohnia  richardi  have  not  been  taken 
from  the  San  Diego  region,  although  the  first  three  are  third,  fourth, 
and  sixth  in  order  of  abundance  in  the  Philippine  region.  On  the 
other  hand,  Sagitta  lyra  and  8.  californica,  in  addition  to  8.  bipunctata, 
were  not  taken  from  the  Philippine  region,  although  the  former  is 


CHAETOGNATHA  COLLECTED  BY  STEAMER  ALBATROSS.          271 

the  most  characteristic  mesoplanktonic  species  in  California  waters. 
Again,  of  those  species  common  to  both  regions,  Sagitta  Jiexaptera  and 
S.  serratodentata  are  second  and  eighth  in  order  of  abundance  in  the 
Philippines  and  tenth  and  second  in  the  San  Diego  region.  Finally, 
aside  from  S.  neglecta,  which  is  rare  in  the  San  Diego  region  and  ob- 
tained by  only  one  haul  from  the  Philippines,  the  order  of  abundance 
of  the  remaining  species  common  to  both  regions  is  as  follows:  S. 
planktonis,  P.  draco,  E.  Tiamata,  and  K.  subtilis  in  the  Philippine 
region;  and  E.  hamata,  K.  subtilis,  S.  planktonis,  and  P.  draco  in  the 
San  Diego  region. 

Taken  in  connection  with  what  is  known  of  the  distribution  of 
chaetognatha  throughout  the  world,  the  above  comparisons  show  that 
the  Philippine  species  are  characteristic  of  the  Tropics  and  warm 
water,  while  those  of  the  San  Diego  region  are,  on  the  other  hand, 
more  characteristic  of  the  Arctics  or  sub-Arctics  and  cold  water. 
As  a  matter  of  fact  there  is  less  difference  between  the  California 
chaetognatha  and  those  of  the  region  about  Spitzbergen  than  there 
is  between  the  California  and  Philippine  faunas. 

Furthermore,  this  sub-Arctic  nature  of  the  California  chaetognatha 
is  not  peculiar  to  that  group.  Calanus  finmarchicus ,  the  commonest 
copepod  of  the  California  coast  is,  according  to  Cleve  (1900,  p.  47), 
a  "characteristic  inhabitant  of  the  Arctic  regions,  along  the  coast 
banks  of  Greenland,  Iceland,  etc."  Similarly,  Eucalanus  elongatus, 
the  second  most  typical  copepod  of  California  waters,  is  "noted  from 
60°  north,  7°  west  in  August  and  the  Skagerak  in  February."  [Cleve 
(1900,  p.  63.)]  Likewise  Acartia  clausii,  obtained  in  abundance  off 
the  pier  of  the  Scripps  Institution,  is  typical  of  the  North  Sea  "  and 
follows  the  coast  of  Norway  to  about  70°  or  74°  north."  [Cleve  (1900, 
p.  42).]  Again,  the  most  prevalent  ctenophore  of  the  California 
region,  PleurolracMa  lachei,  "is  found  in  vast  swarms  in  the  cold 
water  of  Maine  and  Nova  Scotia."  [Esterly  (1914,  p.  28).]  Lastly, 
among  the  diatomaceae,  CJiaetoceros  criophilum  is  the  commonest 
diatom  in  San  Diego  waters,  although  Cleve  (1900,  p.  295)  states 
that  it  is  a  "decidedly  Arctic,  pelagic  species."  Another  common 
San  Diego  CJiaetoceros  is  C.  debile,  but  Cleve  (1900,  p.  296)  says  that 
it  is  abundant  along  the  south  coast  of  Iceland  and  at  the  Faroes." 
Similarly  with  Nitzschia  seriata,  its  "principal  area  of  distribution 
is  between  Scotland,  Iceland,  and  Greenland"  [Cleve  (1900,  p.  336)], 
although  it  is  among  the  common  diatoms  of  the  San  Diego  region. 

So  the  list  might  be  continued.  To  be  sure,  there  are  many 
tropical  and  semitropical  species  occurring  in  California  waters,  but 
they  are  not  the  characteristic  and  prevalent  ones.  These  have  their 
nearest  allies,  not  in  other  parts  of  the  world  at  corresponding  lati- 
tudes, but  in  the  Arctic  and  sub-Arctic  regions.  May  this  not  be 
attributable  in  part  to  the  marked  upwelling  of  cold  bottom  waters 


272 


BULLETIN  100,  UNITED  STATES  NATIONAL  MUSEUM. 


along  the  western  coast  of  America  ?  To  establish  this  would  require 
an  extensive  series  of  collections  off  the  coast  of  Central  and  South 
America,  and  comparisons  of  the  faunas  at  the  same  latitudes  on  the 
two  sides  of  the  Pacific.  But,  if  it  is  true,  it  emphasizes  the  necessity 
of  recognizing  this  fact  in  fisheries  investigations  and  demonstrates 
an  essential  difference  between  the  problems,  economic  and  otherwise, 
of  the  coastal  waters  of  the  eastern  and  western  Pacific. 

That  the  chaetognath  faunas  of  the  two  regions  are  fundamentally 
different  is  made  more  certain  by  the  fact  that  in  four  of  the  five 
Sagitta l  common  to  both  Philippine  and  San  Diego  regions,  the 
Philippine  specimens  have  a  greater  number  of  both  anterior  and 
posterior  teeth.  The  same  is  true  with  respect  to  P.  draco,  and  in 
E.  hamata  the  Philippine  specimens  have  nearly  twice  as  many 
teeth  (21  to  25)  as  do  the  San  Diego  specimens  (10  to  13).  These 
differences  are  mentioned  in  the  preceding  pages  in  connection  with 
the  account  of  each  species,  but  are  better  revealed,  perhaps,  in  the 
following  list: 


Species. 

Anterior  teeth. 

Posterior  teeth. 

Philippines. 

San  Diego. 

Philippines. 

San  Diego. 

8.  enflata  

6-11 
4-8 
8-11 
6-10 
6-10 

4-8 
3-5 
6-9 
4-7 
4-4 

9-15 
12-16 
13-24 
12-18 
10-16 

7-12 
8-11 
13-19 
11-15 
8-9 

S.  serratodentata  

S.  planktonis  
P.  draco  

In  the  case  of  P.  draco  the  differences  may  mean  little,  owing  to 
the  fact  that  only  a  single  very  immature  specimen  is  recorded  from 
the  San  Diego  region.  It  is  interesting,  however,  to  note  that  it  was 
7  millimeters  in  length,  whereas  15  of  the  20  from  the  Philippine 
region  recorded  in  Table  17  are  smaller  and  quite  as  immature,  the 
smallest  being  less  than  5  millimeters  in  length,  although  it  has 
6  to  7  anterior  teeth  and  13  posterior  teeth. 

To  demonstrate  that  the  differences  in  number  of  teeth  given  for 
the  four  species  of  Sagitta  are  significant,  from  10  to  30  or  more 
individuals  of  each  species  were  selected  at  random  from  the  two 
collections,  the  number  of  teeth  counted,  and  the  mean  number  and 
corresponding  probable  errors  computed.  The  results  are  entered  in 
Table  19: 

TABLE  19. — Comparison  of  mean  number  of  teeth  in  specimens  from  the  Philippines  and 
from  the  San  Diego  region. 


Species. 

Anterior  teeth. 

Posterior  teeth. 

Philippines 
(P). 

San  Diego 

(S). 

Difference 
(P-S). 

Philippines 
(P). 

San  Diego 

(S). 

Difference 
(P-S). 

8.  enflata 

8.  29  ±0.256 
5.  61  ±0.160 
9.32±0.133 
8.36±0.200 

6.27±0.035 
3.  80±0.  243 
7.  22±0.  114 
5.  94  ±0.335 

2.  02  ±0.258 
1.81  ±0.291 
2.  10±0.  175 
2.42±0.390 

13.45±0.241 
13.  75±  0.184 
18.  24  ±0.536 
16.  15  ±0.  145 

10.  18±  0.133 
8.  96  ±0.135 
15.44±0.203 
12.60±0.218 

3.  27  ±0.275 
4.  79  ±0.22? 
2.  80±0.  573 
3.  55  ±0.  262 

S.  ner/lecta  
S.  serratodentata  
S.  planktonis. 

hexaptera  is  not  considered  owing  to  loss  of  teeth.     See  p.  245. 


CHAETOGNATHA  COLLECTED  BY  STEAMER  ALBATBOSS. 


273 


Table  19  shows  (1)  that  in  every  case  the  mean  number  of  both 
anterior  and  posterior  teeth  in  Philippine  specimens  exceeds  that  in 
San  Diego  specimens,  and  (2)  that  the  magnitude  of  the  excess  is 
between  5  and  20  times  the  corresponding  probable  error.  That  this 
excess  is  not  merely  an  expression  of  the  larger  size  of  the  Philippine 
specimens  is  evident,  for  the  counts  were  made  on  specimens  of 
Philippine  Sagitta  enflata  between  10  and  21  mm.  in  length  and  on 
San  Diego  specimens  between  10  and  25  mm.;  on  Philippine  S. 
neglecta  between  6  and  8  mm.,  and  on  San  Diego  specimens  between 
8  and  13  mm.;  on  Philippine  S.  serratodentata  between  7  and  11  mm., 
and  on  San  Diego  specimens  between  10  and  17  mm.;  and  on  Philip- 
pine S.  planktonis  between  13  and  27  mm.,  and  on  San  Diego  speci- 
mens between  17  and  26  mm.  Obviously,  some  differential  influence 
is  at  work  in  the  two  regions  causing  an  excess  of  teeth  in  the  Philip- 
pine fauna,  or  a  deficiency  in  the  San  Diego  fauna. 

Unfortunately,  a  similar  comparison  of  Philippine  chaetognatha 
with  those  from  other  regions  of  the  Pacific  is  impossible,  owing  to 
the  fact  that  no  one  except  Fowler  (1906)  has  published  a  series  of 
tooth  counts,  and  he  has  not  kept  the  individual  counts  distinct. 
The  range  of  variation,  however,  in  the  Siboga  material  is  much  the 
same  as  that  in  Philippine  specimens.  This  is  pointed  out  in  the 
foregoing  pages  for  every  species  common  to  the  two  regions,  but 
these  data  are  brought  together  and  amplified  in  Table  20 : 

TABLE  20. — Comparison  of  number  of  anterior  and  posterior  teeth  in  Philippine  species 
and  those  from  the  Siboga  region. 

SAGITTA  ENFLATA. 


L^U, 

specimens 
In  mm. 

Anterior  teeth. 

Posterior  teeth. 

Philip- 
pines. 

Siboga. 

Philip- 
pines. 

Siboga. 

10-15 
15-20 
20-25 
25-30 

6-  7 
7-9 
7-11 

8 

7-  9 
8-9 
8-10 
7-10 

9-12 
13-15 
14-15 
14 

9-14 
12-17 
12-16 
14-17 

SAGITTA  NEGLECTA. 


6.5               4-6 

4-  5 

12-14 

9-10 

7                   5-8 

4-  6 

12-16 

9-12 

7.5 

5-  6 

4-  5 

14-15 

10-13 

8 

5-6 

4-  6 

14-15 

9-14 

SAGITTA  SERRATODENTATA. 


7-  8 

9 

5-9 

13-15 

9-16 

8-  9 

8-  9 

6-9 

14-18 

13-18 

9-10 

8-9 

6-9 

'      16-19 

13-19 

10-11 

8-11 

8    9 

18-24 

15-19 

274  BULLETIN   100,   UNITED  STATES   NATIONAL   MUSEUM. 

TABLE  20. — Comparison  of  number  of  anterior  and  posterior  teeth  in  Philippine  species 
and  those  from  the  Siboga  region — Continued. 


SAGITTA  PLANKTONIS. 


Length  of 
specimens 
in  mm. 

Anterior  teeth. 

Posterior  teeth. 

Philip- 
pines. 

Siboga. 

Philip- 
pines. 

Siboga. 

11-13 
13-15 
15-17 
17-19 
19-21 
21-23 
23-25 
25-27 

7-  9 
9 
9-10 
9-10 
8 
8 
8-  9 
7-  9 

5-  8 
5-  9 
8-  9 
7-  9 
7-11 
8-11 
8-10 
8-  9 

12-10 
16 
15-18 
17-18 
16-17 
16-17 
17-18 
17-18 

13-16 
14-18 
17-18 
16-18 
16-20 
17-20 
18 
18-19 

SAGITTA  PULCHRA. 


10-15 

15-20 
20-25 

5-  8 
6-9 

6-  8 

6-10 
6-10 
7-10 

9-12 
11-13 
10-13 

10-14 
10-15 
12-15 

SAGITTA  DECIPIENS. 

9.0 
11 
12 
12.5 

9-11 
10-11 
9 

8-9 

8 
7 
8 
8-  9 

19-21 
22 

20-21 
19-20 

16 
16 
15-17 
15-18 

SAGITTA  BEDOT1. 

10-12 
12-14 
14-16 

8-10 
8-  9 
8-10 

9-11 
9-13 
9-10 

20-23 
21-25 
22-28 

18-27 
20-32 
21-29 

SAGITTA  FEROX. 

10-12 
12-14 
14-16 

5-  7 
7-  9 
5-  9 

4-  8 

7-  9 
6-  9 

10-12 
12-15 
10-14 

9-13 
10-14 
10-14 

PTEROSAGITTA  DRACO. 

6.0 

7 
7.5 

7-  9 
5-10 
8-  9 

8 
7-10 
8-  9 

11-14 
11-15 
13-16 

12 
11-15 
12-16 

Inspection  of  this  table  reveals  a  pronounced  similarity  in  number  of 
both  anterior  and  posterior  teeth  between  Philippine  and  Siboga  speci- 
mens oiSagitta  enflata,  S.  planktonis,  S.  pulchra,  S.  bedoti,  S.ferox,  and 
Pterosagitta  draco.  In  S.  neglecta,  S.  serratodentata,  and  8.  decipiens 
specimens  from  the  two  regions  agree  in  number  of  anterior  teeth, 
but  those  from  the  Philippines  have  a  greater  number  of  posterior 
teeth.  Even  in  these  instances  the  differences  are  slight  and  prob- 
ably insignificant  except  for  8.  decipiens.  In  this  species  there 
seems  to  be  no  doubt  that  the  Philippine  specimens  have  more 
posterior  teeth  than  Siboga  specimens  of  the  same  length,  although, 
as  pointed  out  on  page  254,  where  the  length  of  animal  was  neglected, 
Fowler's  records  show  a  range  of  13  to  23  posterior  teeth  as  against 
that  of  19  to  22  for  Philippine  specimens. 


CHAETOGNATHA  COLLECTED  BY   STEAMER  ALBATROSS.          275 

On  the  whole  there  is  close  agreement  in  number  of  teeth  between 
specimens  of  species  common  to  the  Philippines  and  the  Siboga 
region,  while  the  same  species  are  represented  in  the  San  Diego 
region,  if  at  all,  by  specimens  having  markedly  fewer  teeth.  In 
the  face  of  this  fact  it  is  evident  that,  as  formerly  (1911,  p.  68) 
stated,  "variation  in  number  of  both  anterior  and  posterioi  teeth 
in  many  species  is  not  referable  to  specific  differences,  but  probably 
to  some  distribution  factor."  When  it  is  recalled  that  a  subnormal 
ocean  temperature  characterizes  the  region  adjacent  to  the  western 
coast  of  America,  due  to  pronounced  upwelling  of  bottom  water, 
and  that  the  chaetognath  fauna  off  southern  and  Lower  California 
is  representative  of  more  northern  latitudes,  it  suggests  that  one  of 
these  distribution  factors  is  temperature.  I  believe  the  small  num- 
ber of  teeth  in  San  Diego  specimens  is  an  expression  of  the  slower 
rate  of  metabolism  due  to  a  lower  ocean  temperature.  This  is  not  a 
new  suggestion,  but  it  is  one  that  merits  thorough  investigation. 
Fowler  (1906,  p.  29),  after  stating  that  specimens  of  Siboga  Sagitta 
serratodentata  have  nearly  twice  as  many  posterior  teeth  as  speci- 
mens of  the  same  length  from  the  Bay  o^f  Biscay,  says:  "It  is  possible 
that  this  may  be  correlated  with  the  respective  temperatures  at 
which  the  specimens  live,  but  a  long  series  of  similar  observations 
from  different  latitudes  would  be  necessary  before  this  could  be 
regarded  as  even  probable." 

LITERATURE  CITED. 

AlDA,  T. 

1897.  The  Chaetognatha  of  Misaki  Harbor.    Annot.  Zool.  Japon.,  vol.  1,  pp. 

79-81,  pi.  4. 
BALDASSERONI,  V. 

1915.  Chetognati.    Raccolte   Planktoniche   fatte   dalla  R.    N.    "Ligura"   nel 

viaggio  di  circonnavigazione  del  1903-05,  vol.  2,  pp.  85-117,  pis.  6-7. 
BERANECK,  E. 

1895.  Les  Che"tognathes  de  la  Bale  d'Amboine.    Rev.  Suiese  Zool.,  vol.  3,  pp. 

137-159,  pi.  4. 
CLEVE,  P.  T.  ;     r 

1900.  The   seasonal   distribution   of  Atlantic   plankton   organisms.    Goteborg. 
Vetensk.    Vitterhets-Samhull.    Handl.  F.,  vol.  4,  Heft  3,  No.  3,  368  pp. 
CONANT,  F.  S. 

1895.  Description  of  two  new  chaetognaths.     J.  Hopkins  Univ.,  Circ.,  vol.  14, 

pp.  77-78,  pi.  1. 
COSTA,  A. 

1869.  Di  un  nuovo  genere  di  Chetognati.    Ann.  Mus.  Zool.  Univ.  Napoli,  vol.  5, 

pp.  54-57. 
DONCASTER,  L. 

1902.  Chaetognatha,  with  a  note  on  the  variation  and  distribution  of  the  group. 
Fauna  and  Geogr.  Maldive-Laccadive  Archip.,   vol.  1,  pp.  209-218, 
pi.  13,  figs.  39-40  in  text. 
ESTERLY,  C.  O. 

1914.  A  study  of  the  occurrence  and  manner  of  distribution  of  the  ctenophora  of 
the  San  Diego  region.    Univ.    Calif.  Publ.  Zool.,  vol.  13,  pp.  21-38. 


276  BULLETIN   100,   UNITED  STATES   NATIONAL  MUSEUM. 

FOWLER,  G.  H. 

1905.  Biscayan  plankton  collected  during  a  cruise  of  H.  M.  S.  Research,  1900. 

Part  3. — The  Chaetognatha.    Trans.  Linn.  Soc.  London,  ser.  2,  vol.  10, 
pp.  55-87,  pis.  4-7. 

1906.  The  Chaetognatha  of  the  Siboga  expedition,   with  a  discussion  of  the 

synonymy   and   distribution   of   the   group.     Siboga   Exped.   Monogr. 
No.  21,  86  pp.,  3  pis.,  6  maps. 
GERMAIN,  L.,  and  JOUBIN,  L. 

1912.  Note  sur  quelques  Che'tognathes  nouveaux  des  croisieres  de  S.  A.  S.  le 

Prince  de  Monaco.    Bull.  Inst.  Oc&inogr.,  No.  228, 14  pp.,  15  figs,  in  text. 
GRASSI,  B. 

1881.  Intorno  ai  Chetognati.    Atti  Inst.  Lombard,  ser.  2,  vol.  14,  pp.  193-213. 
1883.  I  Chetognati.     Fauna  u.  Flora  Golfe  Neapel,  Monogr.  No.  5,  126  pp.,  13  pis. 
KROHN,  A. 

1853.  Nachtragliche  Bemerkungen  iiber  den  Bau  der  Gattung  Sagitta,  nebst  der 
Beschreibung  einiger  neunen  Arten.  Arch.  Naturgesch.,  vol.  19,  No.  1, 
pp.  266-277. 
KRUMBACH,  T. 

1903.  Ueber  die  Greifhaken  der  Chatognathen.    Zool.   Jahrb.    Abt.     System. 

vol.  18,  pp.  579-646,  figs.  A-U  in  text. 
MICHAEL,  E.  L. 

1911.  Classification  and  Vertical  Distribution  of  the  Chaetognatha  of  the  San 
Diego  region,  including  redescriptions  of  some  doubtful  species  of  the 
group.  Univ.  Calif.  Publ.  Zool.,  vol.  8,  pp.  21-186,  pis.  1-8. 

1913.  Sagitta  californica,  n.  sp.  from  the  San  Diego  region,  including  remarks  on 

its  variation  and  distribution.    Univ.  Calif.  Publ.  Zool.,  vol.  11,  pp. 
89-126,  pi.  2. 

1916.  Dependence  of  Marine  Biology  upon  Hydrography  and  necessity  of  quanti- 
tative biological  research.    Univ.  Calif.  Publ.  Zool.,  vol.  15,  pp.  I-XXIII. 
MOBIUS,  K. 

1875.  Vennes.     Die  Expedition  zur  physicalisch-chemischen  und  biologischen 
Untersuchung  der  Nordsee  im  Sommer  1872.    Wiss.  Meeresuntersuch., 
n.  F.,  Abt.  Kiel,  vol.  2,  pp.  158-159. 
D'ORBIGNY,  A. 

1843.  Voyage  dans  1'Amerique  m&idonale.     Paris,  quarto,  vol.  5,  pp.  140-144. 
VON  RITTER-ZAHONY,  R. 

1908.  Chatognathen.    Ber.  Comm.  Erforsch.  ostl.  Mittelmeer,   Zool.  Ergebn., 

vol.  14,  18  pp.,  1  pi. 

1909a.  Expeditionen  S.  M.  Schiff  Pola  in  das  Rote  Meer,  nordliche  und  sudliche 
Halfte,  1895-96,  1897-98.  Chatognathen.  Ber.  Comm.  ozeanogr. 
Forsch.,  Zool.  Ergebn.,  vol.  27,  pp.  43-54,  4  figs,  in  text. 

19096.  Die  Chatognathen  der  Gazelle  Expedition.  Zool.  Anz.,  vol.  34,  pp.  783-793, 
fig.l. 

1910.  Die  Fauna  Siidwest-Australiens.    Lief.  3.    Chatognathen.    Ergebn.  Ham- 

burg, siidw.-austral.  Forsch.,  vol.  3,  pp.  125-126. 

1911.  Revision  der  Chatognethen.    Deutsche  siidpolar  Exped.,  vol.  13,  Zool.  p.  5, 

71  pp.,  51  figs,  in  text. 
STEINHAUS,  O. 

1896.  Die   Verbreitung  der  Chatognathen  im   sudatlantischen  und  indischen 

Ozean.    Inaug.  Diss.  Kiel,  vol.  5,  No.  13,  49  pp.,  1  pi.,  2  charts. 
STRODTMANN,  S. 

1892.  Die  Systematik  der  Chatognathen  und  die  geographische  Verbreitung  der 
einzelen  Arten  im  nordatlantischen  Ozean.  Inaug.  Diss.  Kiel,  vol.  2, 
No.  10,  47  pp.,  2  pis. 


CHAETOGNATHA  COLLECTED  BY   STEAMER  ALBATROSS.          277 

EXPLANATION  OF  PLATES. 

[All  figures  drawn  with  camera  luclda.] 
PLATE  34. 

FIG.    1.  Sagitta  philippini,  new  species.     X  18. 

.    2.  Anterior  teeth  and  few  of  posterior  teeth  of  S.  philippini.     X  250. 

3.  Vestibular  ridge  of  S.  philippini.     X  250. 

4.  Seizing  jaws  of  S.  philippini.     X  800. 

PLATE  35. 

FIG.    5.  Sagitta  pukhra  Doncaster.     X  8. 

6.  Sagitta  bedoti  Be>aneck.     X  8. 

7.  Sagitta  ferox  Doncaster.     X  8. 

8.  Sagitta  dccipiens  Fowler.     X  18. 

9.  Sagitta  neglecta  Aida.     X  18. 

PLATE  36. 

FIG.  10.  Eukrohnia  richardi  Germain  and  Joubin.     X  6. 

11.  Pterosagitta  draco  (Krohn).     X  25. 

12.  Pterosagitta  draco  with  collarette  partly  torn  away  and  with  no  vestige  of 

ovary  or  seminal  vesicle.     X  25. 

13.  Pterosagitta  draco  with  fully  mature  ovaries  and  with   collarette  almost 

entirely  missing.     X  25. 

PLATE  37. 

FIG.  14.  Teeth  of  Eukrohnia  hamata  (Mobius).     X  100. 

15.  Teeth  of  Eukrohnia  richardi  Germain  and  Joubin.     X  100. 

16.  Vestibular  ridge  of  Sagitta  minima  Grassi.     X  400. 

17.  Seizing  jaw  of  Sagitta  minima.     X  800. 

18.  Portion  of  vestibular  ridge  and  posterior  teeth  of  Sagitta  dccipiens  Fowler. 

X  400. 

19.  Vestibular  ridge  of  Sagitta  pukhra  Doncaster.     X  400. 

20.  Vestibular  ridge  of  Sagitta  bedoti  Be"raneck.     X  400. 

21.  Vestibular  ridge  of  Sagitta  ferox  Doncaster.     X  400. 

22.  Seizing  jaw  of  Sagitta  decipiens  Fowler.     X  800. 

23.  Seizing  jaw  of  Sagitta  pukhra  Doncaster.     X  800. 

24.  Seizing  jaw  of  Sagitta  bedoti  Be>aneck.     X  800. 

25.  Seizing  jaw  of  Sagitta  ferox  Doncaster.     X  800. 

26.  Seizing  jaw  of  Eukrohnia  richardi  Germain  and  Joubin.     X  800. 

27.  Seizing  jaw  of  Eukrohnia  hamata  (Mobius).     X  800. 

PLATE  38. 

FIG.  28.  Posterior  extremity  of  a  small  mature  Sagitta  enflata  Grassi.     X  25. 

29.  Posterior  extremity  of  a  mature  Sagitta  minima  Grassi.     X  25. 

30.  Ventral  view  of  anterior  extremity  of  Sagitta  bedoti  Be"raneck.     X  50. 


U.    S.    NATIONAL    MUSEUM 


BULLETIN    ICO      PL.   34 


CHAETOGNATHA  COLLECTED  IN  PHILIPPINE  ISLANDS. 

FOR    EXPLANATION    OF    PLATE    SEE    PAQE    277. 


U.    S.    NATIONAL    MUSEUM 


BULLETIN    100      PL.    35 


CHAETOGNATHA  COLLECTED  IN  PHILIPPINE  WATERS. 


U.    S.    NATIONAL    MUSEUM 


BULLETIN    100      PL.    36 


S 


CHAETOGNATHA  COLLECTED  IN  PHILIPPINE  WATERS. 


U.    S.    NATIONAL    MUSEUM 


BULLETIN    100       PL.    37 


23  24  25 

CHAETOGNATHA  COLLECTED  IN  PHILIPPINE  WATERS. 


U.    S.    NATIONAL    MUSEUM 


BULLETIN    100       PL. 


•li. 


CHAETOGNATHA  COLLECTED  IN   PHILIPPINE  WATERS. 


INDEX. 


Page. 

bedotil  (Sagitta),  distribution  of 257 

measurements  of 257 

Philippine  records  of  occur- 
rence   258 

redescription  of 255 

chaetognatha,  comparison  of  Philippine  and 

San  Diego  faunas 236, 270 

distribution  relative  to  fishery 

problems . 237, 272 

distribution   relative   to   up- 
welling  water 271,275 

key  to  genera  of 238 

significance  of  variability  in 

number  of  teeth 272 

species  collected 235 

validity  of  genera 237 

decipiens  (Sagitta),  distribution  of 255 

measurements  of 255 

Philippine  records  of  oc- 
currence   256 

redescription  of 254 

resemblance  to  S.  phil- 

ippini 241 

variability  in  number  of 

teeth 254 

distribution  of  E  ukrohnia  hamata 267 

Krohnitta  subtilis 270 

Pterosagitta  draco 265 

Sagitta  bedoti... 257 

S.decipiens 255 


ferox. 


neglecta 

planktonis 

pulchra 

serratodentata 

draco  (Pterosagitta),  distribution  of 

measurements  of 

Philippine  records  of  oc- 

rence 

variability  in  number  of 

teeth 

enflata  (Sagitta),  distribution  of 

measurements  of 

peculiarities  in  maturation 

of 

Philippine  records  of  occur- 
rence  

variability  in  number   of 

teeth 

Eukrohnia,  key  to  species  of 

validity  of 


ferox  (Sagitta),  distribution  of 260 

measurements  of 260 

Philippine  records  of  occur- 
rence   262 

redescription  of 259 

resemblance  to  S.  robusta 259 

genera,  key  to 238 

validity  of 237 

hamata  (Eukrohnia),  distribution  of 267 

variability  in  number 

of  teeth 266 

hexaptera  (Sagitta),  distribution  of 246 

loss  of  teeth 245 

measurements  of 245 

Philippine  records  of  oc-  • 

currence 247 

Heterokrohnia  (validity  of) 237 

Keys,  discussion  of 237 

to  genera 238 

species  of  Eukrohnia 240 

Sagitta 238 

Spadella 239 

Krohnitella  (validity  of) 237 

Krohnitta  (validity  of) 237 

macrocephala  (Sagitta) 250 

measurements  of  Eukrohnia  richardi 267 

Krohnitta  subtilis 269 

Pterosagitta  draco 265 

Sagitta  bedoti 257 

S.decipiens 255 

enflata 243 

ferox 260 

hexaptera 245 

neglecta 258 

pulchra 252 

serratodentata 249 

minima  (Sagitta),  redescription  of 248 

neglecta  ( Sagitta),  distribution  of 258 

measurements  of 258 

variability  in  number  of 

teeth 258 

philippini  (Sagitta),  description  of 240 

resemblance  to  S.  decip- 

iens 241 

validity  of 242 

planktonis  (Sagitta),  distribution  of 263 

Philippine  records  of  oc- 
currence   264 

variability  in  number  of 

teeth 263 

Pseudosagitta  (validity  of) 237 

Pterosagitta  (validity  of) 237 

m 


IV 


INDEX. 


Page. 

pulchra  (Sagitta),  distribution  of 252 

Philippine  records  of  oc- 
currence    264 

variability  in  number  of 

teeth 263 

richardi  (Eukrohnia),  measurements  of 267 

validityof 267 

Sagitta,  key  to  species  of 238 

species  collected 235 

validityof 237 

serratodentata  (Sagitta),  distribution  of 250 

measurements  of . . .  249 
Philippine    records 

of  occurrence 250 

variability  in  num- 
ber of  teeth 249 


Page. 

Spadella,  key  to  species  of 239 

validityof 237 

subtilis  ( Krohnitta),  distribution  of 270 

measurements  of 269 

teeth  (variability  in  number  of),  Eukrohnia 

hamata...  266 
Pteros  agit- 

ta  draco..  264 
Sagitta    de- 

cipiens . . .  254 

S.  enflata. . .  242 

neglecta  .  258 
plankto- 

nis 263 

serrato- 
dentata 249 
Signifi- 
cance of  272 


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